NTU Supervisors & Projects (School of Electrical & Electronic Engineering)

S/N Supervisor Appointment Email Contact Title and Short Abstract of Proposed Ph.D. Project Research Area

1-1 Arokiaswami Alphones

Assoc Prof ealphones@ntu.edu.sg Title: Metamaterials and Peridoic structures Abstract: Recently leaky wave phenomena from left handed wave guides are

very interesting research topic, especially for their composite forms of left

and right handed transmission line where wave can be scanned from

backward to forward directions continuously through zero order propagation

constant by changing frequency. They are expected small leaky wave

antenna for communication use. Few years back we have proposed double

periodic left handed transmission line where capacitance or inductance is

periodically loaded in the line.

Realizing compact antennas and filters using metamaterials concept would be attempted in this work.

Info-Communications

1-2 Arokiaswami Alphones

Assoc Prof ealphones@ntu.edu.sg Title: Metamaterial assisted Wireless Power Transfer System Abstract: WIRELESS POWER TRANSFER (WPT) systems have been extensively investigated in the last few years. WPT technology can be used in a wide range of industrial applications such as biomedical implants, robotics, consumer electronics and electric vehicle (EV) charging to eliminate charging hazards and drawbacks related to cables. In this project, an analytical method to calculate the scattering parameters of a wireless power transmission link composed of electrically small single loop resonators will be attempted. The method has to consider all the different couplings in the structure. First, the approach to be used to find the S-parameters for links composed of circular and rectangular resonators. The model is then to be used to find the optimal topology for a given transmission distance. Validation of the model has to be done by comparing its results with experimental measurements.

Info-Communications

1-3 Arokiaswami Alphones

Assoc Prof ealphones@ntu.edu.sg Title: Perturbation Analysis on Grating Coupler Abstract: Optical integrated circuits consist of multiplexers,input, output couplers. This project will theoretically investigate with rigorous analysis on periodically modulated grating structures in optical domain.

Info-Communications

2-1 Chau Lap Pui Assoc Prof elpchau@ntu.edu.sg Title: Human motion retrieval system based on human skeleton extraction Abstract: As motion capture device becomes more popular, the motion data sets are becoming larger. So efficient retrieval method for the human motion database is very important. This project is to develop an efficient retrieval method that requires efficient indexing scheme and robust similarity measure to represent motion data.

Info-Communications

2-2 Chau Lap Pui Assoc Prof elpchau@ntu.edu.sg Title: Contrast Enhanced Vision for Deepwater Monitoring System Abstract: Current approaches to image processing for contrast enhancement rely on standard models of signal-to-noise ratio (SNR). Novel optical characterization with associated signal processing can enable dramatic increase in image and video sharpness and clarity. The proposed research can apply to vision based operation under deepwater environment. This proposal will describe a feasible method to enhance deepwater optical image and video. Deepwater vehicles namely Remotely Operated Vehicles (ROV) generally comes with optical sensors for their capability of remote operation. Therefore, deepwater vision is an important issue in maritime application. Different from the common video, deepwater video suffer from poor visibility due to the scattering and light distortion. Owing to the challenging deepwater conditions and the light dissemination, conventional image and video processing methods cannot be applied directly in deepwater video. The proposed research intends to alleviate the drawbacks of the low light saturation to obtain a clear vision.

Info-Communications

2-3 Chau Lap Pui Assoc Prof elpchau@ntu.edu.sg Title: Feature Extraction and Representation for Human Action Recognition Abstract: In this project, we would like to propose a new framework for the real-time realization of human action recognition. New feature descriptors are developed that are tolerant for illumination change which can be run in various configurations on a platform suitable for use as an embedded system. This proposed framework will also be extended to support multiple camera in order to improve the accuracy.

Info-Communications

2-4 Chau Lap Pui Assoc Prof elpchau@ntu.edu.sg Title: Human motion retrieval system based on human skeleton extraction Abstract: As motion capture device becomes more popular, the motion data sets are becoming larger. So efficient retrieval method for the human motion database is very important. This project is to develop an efficient retrieval method that requires efficient indexing scheme and robust similarity measure to represent motion data.

Info-Communications

3-1 Yap Kim Hui Assoc Prof ekhyap@ntu.edu.sg Title: Mobile Visual Object Search Abstract: The objective of mobile visual search is to recognize the objects of the captured images, and then retrieve relevant information of the recognized objects. An example of such applications is mobile consumer product recognition and recommendation service where the user can capture the image of a consumer product (e.g. book/CD/DVD cover, logo, advertisements, etc.) and then use the system to recognize it and retrieve relevant information such as the brand name, the price comparison and recommendation, etc. The project will study key issues including visual content analysis, large-scale visual search and recognition, and user-system interaction.

Info-Communications

3-2 Yap Kim Hui Assoc Prof ekhyap@ntu.edu.sg Title: Mobile Media Content and Context Analysis Abstract: The objective of this project is to study and develop content and context analysis for mobile media applications. In particular, it aims to develop and transform a mobile device into a portable information terminal that renders various situation-aware mobile services, e.g. mobile landmark recognition, augmented-reality city guide, and consumer product recognition. The project will investigate key issues including content and context analysis, efficient visual search and recognition, and user-system interaction.

Info-Communications

3-3 Yap Kim Hui Assoc Prof ekhyap@ntu.edu.sg Title: Mobile Media Visual Object Search Abstract: The growing usage of mobile devices has led to proliferation of many mobile applications. Amongst them, mobile media visual object search is an emerging application that is receiving growing attention recently. The objective of mobile visual search is to recognize the objects of the captured images, and then retrieve relevant information of the recognized objects. An example of such applications is mobile consumer product recognition and recommendation service where the user can capture the image of a consumer product (e.g. book/CD/DVD cover, logo, advertisements, etc.) and then use the system to recognize it and retrieve relevant information such as the brand name, the price comparison and recommendation, the shops nearby selling the product, etc. The project will study key issues including visual content analysis, large-scale visual search and recognition, and user- system interaction. An example of the developed system similar to this project can be viewed at Google Goggle Lab video http://www.youtube.com/watch?v=9apkpwDRI10.

Info-Communications

3-4 Yap Kim Hui Assoc Prof ekhyap@ntu.edu.sg Title: Mobile Media Content and Context Analysis and Applications Abstract: The objective of this project is to study and develop content and

context analysis for mobile media applications. In particular, it aims to

develop and transform a mobile device into a portable information terminal

that renders various situation-aware mobile services, e.g. mobile landmark

recognition, augmented-reality city guide, and consumer product recognition.

The project will investigate key issues including content and context analysis,

efficient visual search and recognition, and user-system interaction. An

example of the developed system similar to this project can be viewed at

Google Goggle Lab video

http://www.youtube.com/watch?v=9apkpwDRI10.

The project will also aim to address the challenges of mobile environments including low/moderate processing power of mobile devices, fast response-time requirement of users, and limited battery life of mobile phones.

Info-Communications

4-1 Tang Xiaohong Assoc Prof exhtang@ntu.edu.sg Title: Development and Characterization of the Polymer-based Thin-film Photovoltaic Solar Cells Abstract: Polymer-based thin film photovoltaic solar cells are important in solar cell applications. In this project polymer semiconductor/fullerene bulk heterojunction photovoltaic solar cells will be developed and characterized. The charge carriers transportation in the solar cell will be investigated in order to obtain high power conversion efficiency of the devices.

Electronics

4-2 Tang Xiaohong Assoc Prof exhtang@ntu.edu.sg Title: MOVPE growths of narrow bandgap semiconductor alloys for mid-infrared photonics Abstract: Powerful and easy-to-use lasers operation in the mid-infrared (IR) range, 2 < m to 4 < m, are very important for a variety of military, biomedical, environmental and industrial applications, including range-finding, laser surgery and remote trace-gas sensing, etc. In this project, MOVPE growth of high quality III-V semiconductors for mid-IR photonics applications will be investigated and studied.

Electronics

4-3 Tang Xiaohong Assoc Prof exhtang@ntu.edu.sg Title: Charge transportations in high efficiency Peroviskite solar cells: Abstract: Currently Peroviskite based solar cells have attracted much attentions in solar energy harvesting researches. Hybrid organic–inorganic perovskites, most commonly CH3NH3PbI3 or a close variant, were first introduced to the photovoltaic community in 2009. In subsequent years, cells based on such materials have shown an unprecedented increase in solar-to-electrical power conversion efficiency — from <10% in mid-2012 to over 20% at present. In this research, charge transportation and collections in the pervoskite solar cell will be studies theoretically and experimentally, which will be very important to understand the operation of the solar cells and developing high efficient solar cells.

Electronics

4-4 Tang Xiaohong Assoc Prof exhtang@ntu.edu.sg Title: High efficient compound semiconductor nanostructures based hybrid organic solar cells: Abstract: Organic polymer thin film solar cells are attractive because of their solution based fabrication process, potential cheap roll-to-roll mass production and importance in wearing optoelectronics applications. Because of the limitation of the suitable energy bandgap donor polymers, the power conversion efficiency of the polymer based organic photovoltaic solar cells is limited <10%. On the other hand, inorganic compound semiconductors have a wide range energy bandgaps available. If this research, compound semiconductor nanostructures, e,g nanowires, quantum dots, etc, based hybrid organic photovoltaic solar cells will be studied and fabricated.

Electronics

4-5 Tang Xiaohong Assoc Prof exhtang@ntu.edu.sg Title: Controllable compound semiconductor nanostructures for photonic applications: Abstract: III-V compound semiconductors with their wide range of energy bandgap, excellent optical properties and high electron mobility are very important in photonic applications and high speed electronic devices. In this research, compound semiconductor nanostructures will be developed using metal-organic vapor phase epitaxy (MOVPE) technology. Their physical properties will be characterized and their applications in photonic devices will be explored.

Electronics

4-6 Tang Xiaohong Assoc Prof exhtang@ntu.edu.sg Title: MOVPE growth of semiconductor quantum dots for mid-infrared photonics: Abstract: Spanning the wavelength range of 2–20μm, the mid-infrared (mid-IR) is a spectral region of tremendous scientific, biomedical and technological interest. It contains the strong characteristic vibrational transitions of many important molecules, which makes the mid-IR lasers crucial for applications in spectroscopy, materials processing and chemical and biomolecular sensing. The atmospheric transmission window of 2–5μm and 8-13μm in which the Earth’s atmosphere is relatively transparent, is also important for atmospheric, security and industrial applications such as remote explosive detection, countermeasures against heat-seeking missiles and covert communication systems. Furthermore, 3μm laser is a very good ‘Laser Scalpel’ for non-contact laser surgery because of the highest absorption of tissues at 2.8μm. In this research, high quality, high density and uniform III-V semiconductor quantum dots for mid-IR photonic devices application will be synthesized using metal-organic vapor phase epitaxy (MOVPE) technology and studied.

Electronics

5-1 Andy Khong Assoc Prof andykhong@ntu.edu.sg

Title: Data Analytics for Learning Science Abstract: The aim of this research is to develop data analytics to understand human learning behaviour. This project involves data mining and machine learning which is applied on understanding human behaviour as they go through online courses. This interdisciplinary research will incorporate learning science and learning pedagogy.

Info-Communications

5-2 Andy Khong Assoc Prof andykhong@ntu.edu.sg

Title: Acoustic signal processing and acoustic enhancement technologies Abstract: The aim of this research is to develop algorithms to achieve audio enhancement in a noisy environment. This involves the development of array signal processing algorithms, which can applied to microphone array in a noisy environment. Potential applications include surveillance and meeting scenarios where the quality of sound is important.

Info-Communications

6-1 Law Choi Look Assoc Prof ecllaw@ntu.edu.sg Title: Ultra low power wireless communication devices for E- sensing in dense cluttered environments Abstract: Indoor environments and underground environments are examples

of dense cluttered environments. These environments are known to be

hostile to wireless communication signals due to multipath signals. Current

low power wireless communication technologies such as Zigbee and

Bluetooth are highly susceptible to multipath signals (suffers from flat fading),

resulting in degraded performances. Wide bandwidth signaling (such as OFDM)

is currently used to overcome the impairments caused by multipath signals.

However, complex transceiver circuits are used resulting in increased power

consumption. Ultra-wideband impulse radio (UWB-IR) is an innovative

signaling method whereby the carrier frequency is turned on for a few

cycles in a data symbol. This short pulse duration results in multipath signal

arrivals which do not interfere with the direct path transmission. Precise

ranging based on time of arrival of the direct path signal can also be extracted.

The objective of this proposed project is to investigate hardware circuits for energy efficient transmission of environmental data (e.g temperature, light intensity, etc) from numerous spatially distributed sources to a central receiver using UWB-IR signals. The investigations include novel circuits for energy efficient generation of UWB-IR electro- magnetic waves with superimposed data modulation and energy harvesting circuits for powering up the data source. Novel antenna array techniques exploiting the UWB-IR multipath channel characteristics will be investigated to improve the receiver sensitivity.

Info-Communications

6-2 Law Choi Look Assoc Prof ecllaw@ntu.edu.sg

Title: Energy efficient large scale wireless sensor network for E- sensing in dense cluttered environments Abstract: Indoor environments and underground environments are examples

of dense cluttered environments. These environments are known to be

hostile to wireless communication signals due to multipath signals. Current

low power wireless communication technologies such as Zigbee and

Bluetooth are highly susceptible to multipath signals (suffers from flat fading),

resulting in degraded performances. Wide bandwidth signaling (such as OFDM)

is currently used to overcome the impairments caused by multipath signals.

However, complex transceiver circuits are used resulting in increased power

consumption. Ultra-wideband impulse radio with its large signal bandwidth

and simple transceiver circuits is well suited for ultra low power wireless

communication E- sensing in dense cluttered environments.

The objective of this proposed project is to investigate medium access control and network protocols for energy efficient large scale wireless sensor networks with simultaneous nodes localization capability. These wireless sensor networks are expected to work in dense cluttered environments for E-sensing applications such as environmental monitoring, industrial monitoring and target tracking. IR-UWB physical layer will be used in the study. Channel parameters sensed from the IR-UWB signals will be used to optimize time slot allocation in medium access control, multi-hop routing and nodes localization. The study is expected to yield optimized sensor nodes clustering, time slot allocation, delay in sensed information transfer to cluster head and tradeoff with energy usage.

Info-Communications

7-1 K Radhakrishnan Assoc Prof eradha@ntu.edu.sg Title: High Electron Mobility Transistor Structures for High Power RF Devices using Gallium Nitride based wide bandgap Semiconductors on Silicon Abstract: Epitaxial growth (Molecular Beam Epitaxy and Metalorganic CVD) of novel GaN-based heterostructures on silicon as low- cost solution for high speed and high power RF devices. Novel stress mitigation techniques to grow crack-free layers. Advanced electrical (Hall, I-V, C-V) surface (AFM), structural (XRD, TEM) and optical (Photoluminescence, Raman) characterizations to assess the quality of layer structures. Submicron HEMT device fabrication and DC and RF characterization. Strong interest in semiconductors and materials science is advantageous.

Electronics

7-2 K Radhakrishnan Assoc Prof eradha@ntu.edu.sg Title: Studies on epitaxial growth and characterization of lattice matched InAlN/GaN Heterostructures on silicon for high power applications Abstract: GaN-based wide band gap semiconductors are attractive for light

emitting diodes, solar cells and ultraviolet photodiodes applications. They

are also of interest for wireless network base stations, satellite

communication systems and compact digital radar applications where GaN-

based devices can multiply the efficiency of amplifiers. However,

improvements in GaN-based High Electron Mobility Transistors (HEMTs) are

limited by the fundamental parameters of established AlGaN/GaN

heterostructures. The objective of this project is to explore new

heterostructures using InAlN/GaN alloys and enhance the potential power

density of HEMTs. InAlN alloys are attractive due to their wide bandgap (0.6

to 6.2 eV) and lattice matching capability with GaN. Extremely high electron

gas density coupled with polarisation fields in the heterojunction offers

power densities of 30W/mm at 2 to 12 GHz.

The research will focus on optimizing the growth of InAlN /GaN HEMT layers on Si using Molecular Beam Epitaxy (MBE) and/or metalorganic vapour deposition techniques to demonstrate high performance HEMT devices. Since MBE is a low temperature process, it offers great control over the growth and composition for In-based alloys. A novel 2-step approach (low/high temperature) will be used to avoid the formation of amorphous layer as well as metal-Si clusters on the interface between the substrate and the epilayer. This approach is expected to prevent the metal diffusion into the buffer layer and reduce the defects and the integrity of buffer layers for devices. MOCVD growth is attractive for higher throughput and the ability to grow on large area substrates. However, growth of ternary indium based alloys may be challenging by MOCVD as the growth takes place at elevated temperatures leading to phase separation. Novel layer structure design and growth optimization studies will be conducted to address this issue. Advanced microscopic and spectroscopic characterization techniques including electrical measurements such as RHEED, AFM, Hall, XRD, TEM, SEM, Raman, etc will be used to analyse the heterostructures and assess the composition, thickness, electrical, surface and structural properties of the layer structures.

Electronics

7-3 K Radhakrishnan Assoc Prof eradha@ntu.edu.sg Title: Gallium Nitride -based Ultraviolet (UV) photodetectors on Silicon Abstract: UV detectors have several applications such as UV imaging, solar UV

measurements, flame sensors, missile plume detection, spatial optical

communications, biological and chemical sensors and so on.

Conventional silicon-based UV detectors have some major intrinsic limitations such as aging due to exposure to radiation of much higher energy than the Si bandgap, reduced quantum efficiency in the deep-UV range, significant loss of effective area due to the need to use filters and cooling if low dark current is required. On the other hand, Group III Nitrides offer advantages over Si for UV detection. Nitrides have a direct bandgap (which confers the photodetector with a highly improved spectral selectivity). Moreover, the photodetector cut-off frequency can be engineered by changing the mole fraction in their ternary alloys. The saturation velocity in GaN is a few times higher than in GaAs or Si, enhancing the transient response of the photodetectors.

In this project, GaN-based ultraviolet (UV) detectors on Si with high performance will be developed. Compared to conventional method, GaN epitaxial growth on Si is promising and cost-effective solution, especially, such scheme has the potential advantages of monolithically integrating GaN- devices with Si-microelectronics, giving circuit designers unprecedented flexibility to use the best material and devices for each function. GaN and AlGaN layer structures of appropriate composition will be grown on Si substrates using molecular beam epitaxy (MBE). Structural, electrical and optical characterizations will be carried out to optimize the quality, composition and thickness of the layers suitable for photodetector applications. The (Al)GaN MSM (metal-semiconductor-metal) UV detectors (.<280 nm) will be designed and fabricated. The fabricated GaN/Si UV detectors are aimed to exhibit high performance such as low dark current and high responsivity. Further studies may include addressing the dark current issues using insulating layers such as ZrO2 and HfO2.

Electronics

8-1 Ling Keck Voon Assoc Prof ekvling@ntu.edu.sg Title: Distributed Control and Optimization of Smart Grids Abstract: This is collaboration with Energy Research Institute @NTU (http://erian.ntu.edu.sg/Pages/Home.aspx) to develop and test advanced state estimation, control and optimization strategies for smart grid. In particular, we will be looking at scalable and distributed optimization algorithms. The potential candidate should have an interest in power system engineering, and mathematically inclined. Programming skills will be an added advantage

Electrical & Systems

8-2 Ling Keck Voon Assoc Prof ekvling@ntu.edu.sg Title: Model Predictive Control on a Chip Abstract: The project aims to accelerate computation of model predictive control algorithms (a form of constrained optimization to be carried out online and in real-time) on special purpose hardware, such as a Field-Programmable Gate Array (FPGA), or a Graphics Processor Unit (GPU). Experience in digital circuit and system design and MATLAB would be useful.

Electrical & Systems

9-1 Ma Maode Assoc Prof emdma@ntu.edu.sg Title: Security Enhancements for the M2M Communication in the Internet of Things Abstract: The Internet of Things (IoT) will consist of billions of digital devices,

people, services and other physical objects having the potential to

seamlessly connect, interact and exchange information about themselves and

their environment. It helps to optimize operations, reduce costs, boost

productivity and improve lives. IoT represents the next evolution of the

Internet, taking a huge leap in its ability to gather, analyze, and distribute data

that we can turn into information, knowledge, and, ultimately, wisdom.

Thus, in this project, a security scheme will be constructed to improve the security of IoT in the layer of 6LoWPAN with the consideration of large scale structure and resource constraint.

Info-Communications

9-2 Ma Maode Assoc Prof emdma@ntu.edu.sg

Title: Enhancements of Cyber Security for Smart Grid Systems Abstract: The smart grid is a promising power delivery infrastructure

integrated with communication and information technologies. It could

generate enormous economic, environmental and social benefits through

the bi-directional communication and electricity flow, as well as the

integration of vast distributed energy resources.

In order to address such threats, existing security standards and technologies should be closely examined and investigated to ensure the feasibility in the smart grid systems. In addition, new communication protocol or security schemes will be designed supported by popular log ic theorem to prove the correctness, and be tested through simulation to prove the robustness and scalability.

Info-Communications

10-1

Arindam Basu Asst Prof arindam.basu@ntu.edu.sg

Title: Neuromorphic Smart Sensors for Implantable Brain Machine Interfaces Abstract: Brain machine interfaces (BMI) have been developing rapidly in the

last 10 years. One of the goals in implantable BMI systems is to record

and interpret neural signals from the motor cortex (or the part of the brain

that plans body movements or motor activity) and use it to control artificial

actuators. This brings hope for people with paralysis to be able to control

artificial limbs with their thoughts.

Current solutions transmit all data to an off-chip device for processing. This results in a huge wireless data rate and the concomitant power dissipation prevents scalability. In this research, we take inspiration from how the brain processes these signals and develop artificial “neural networks” on-chip to directly process and interpret these brain signals on-chip leading to a scalable neuroprosthetic of the future.

Electronics

10-2

Arindam Basu Asst Prof arindam.basu@ntu.edu.sg

Title: Morphological Learning in Spiking Neurons: A New Hardware Efficient Machine Learning Method Abstract: Traditionally neural networks have used some form of gradient

descent or Hebbian learning based weight change method to perform

learning. This is true in both software and hardware systems. However, in

analog VLSI implementations of large scale neural networks, it is very difficult

to implement high resolution synaptic weights due to the increased

mismatch between transistors in sub-micron processes. Using digital VLSI is

not effective here due to the large area and power overhead needed to

implement a multiplier to be used as a synapse. Interestingly, biology is

faced with the same challenge and measurements in the human brain show

that the synapses have at most 2-4 different weight values reliably! Does

biology perform learning in a different way?

In an attempt to answer this question, we will take inspiration from the fact that all biological neurons have different morphologies, i.e. different shapes or structure and connections to other neurons are “grouped” together on different input dendritic branches separately. Recent studies have shown non-linear responses from each branch leading to a new mathematical model for a neuron. What if the neuron can decide “which” input connections to group together on one branch, i.e. what is its best morphology or structure? Each grouping leads to different input-output functions and hence leads to different classification boundaries. In this research, we will explore hardware efficient algorithms to perform machine learning using this new paradigm.

Electronics

11-1

Poenar Daniel Puiu

Assoc Prof epdpuiu@ntu.edu.sg Title: Microfluidic in vitro model of epithelial cells & their tight junction assessment

Abstract: The lining of the gastrointestinal tract (GIT) is the largest surface exposed to the external environment in the human body where the absorption of food and drug takes place. Understanding the mechanism of compounds absorption through the small intestinal epithelium, and how specific organs respond to these compounds is critical for toxicological evaluation of new drugs and food screening. Additionally, the mechanism of intestinal barrier modulation and its transport function is of high importance for nutrition, pharmaceutical and pathological sciences to understand the diseases pathogenesis and the development of new therapeutic approaches. The epithelial cells act as a selectively permeable barrier (permitting the absorption of nutrients, electrolytes, and water while maintaining an effective defense against toxins) and their permeability depends on the regulation of the intercellular tight junctions (TJs) between them. This barrier function is severely compromised when epithelial cells (ECs) are lost, for example, after exposure to microorganisms, and their products.

This project will investigate the role of the epithelial barrier in transportation of pharmaceutical and biological compounds through the intestinal lumen. For this purpose, an in vitro model of the intestinal lumen -comprising a monolayer of epithelial cells (ECs) and a lining mucus layer produced by mucus-producing cell co-culture- will be integrated within a three-dimensional (3D) microfluidic biochip. To achieve this goal, the student will perform first a Literature review, design the 3D microfluidic structure of the biochip with integrated sensors and perform various FEA simulations to optimize its performance, design the fabrication process and assist in the fabrication of the devices, and finally test & measure them. The project will be carried out in collaboration with Dr. Qasem Ramadan of the Institute of Microelectronics (IME), Singapore, who will be co-supervisor.

Electronics

11-2

Poenar Daniel Puiu

Assoc Prof epdpuiu@ntu.edu.sg Title: Plasma etching of dielectrics for sub-50 nm structures

Abstract: Scaling down devices dimensions is still the mainstream trend in CMOS technology. Ensuring the capability to perform high-precision plasma etching of dielectrics for sub-50 nm sized structures is essential for continued miniaturization in CMOS technology.

Fabricating devices with critical dimensions smaller than 50 nm is possible by using ArF-laser lithography but the role of plasma etching in this development is very critical. This is because dielectrics can be used as hard masks in the fabrication of MOS transistor gates, and this complicates the etching process, introduces additional sources of error and makes downscaling of etch windows much more difficult. Therefore, the post-etch resolution capabilities obtainable using Ar-F lithography are enhanced with additional trimming or shrinking methods.

Direct Self–Assembly (DSA) of block copolymers is a widely explored method to obtain patterns used as masks to etch holes or trenches. However, important challenges concerning material development, etch processes and integration still need to be addressed for full adoption of DSA in manufacturing.

This project will explore other alternative ways of downscaling etch windows, based on combining two methods:

1) 1) Controlled plasma polymerization on the resist openings sidewalls, which is followed by etching of first hard mask;

2) 2) Shrinking the window opening in the first hard mask (Si-based dielectric initially deposited by PECVD) followed by etch back, thus leaving spacers on sidewalls resulting in reduction of bottom CD.

Further stages of development will include etch optimization for bottom layer which, depending on integration flow, may serve as a functional layer or as a 2nd hard mask. In the latter case it is planned to investigate comparatively the traditional hard mask of TiN with new hard masks such as AlN, Al2O3 and Cr which provide very high selectivity in fluorine-based plasma and potentially allow to achieve much higher aspect ratios in the underlying functional layers. The project will be carried out in collaboration with Dr. Vladimir Bliznetsov of the Institute of Microelectronics (IME), Singapore, who will be co-supervisor.

Electronics

12-1 Teh Kah Chan Assoc Prof ekcteh@ntu.edu.sg Title: Studies robust and energy-efficient cooperative communication systems over fading channels Abstract: In this project, student will first conduct literature survey on existing cooperative communication systems. Some existing results will also be reproduced and compared. The effect of fading channel will be taken into consideration. Following that, new robust and energy-efficient algorithms will be proposed to improve the system performance. The corresponding system performance and complexity will be compared with some existing techniques.

Info-Communications

12-2 Teh Kah Chan Assoc Prof ekcteh@ntu.edu.sg Title: Development and study of novel frequency-hopped multiple- access receiver Abstract: Recently, frequency-hopped spread-spectrum systems have been widely used in commercial and military applications. In this project, the student will first conduct literature survey on existing frequency-hopped multiple-access systems. Following that, the student will study and develop a novel receiver structure for frequency-hopped multiple-access systems over fading channels. Maximum-likelihood receiver will be proposed and Matlab simulation will be conducted to study the bit-error rate performance of the proposed receiver structure.

Info-Communications

13-1 Xiao Gaoxi Assoc Prof egxxiao@ntu.edu.sg Title: Resilience of complex systems: evaluation and enhancement Abstract: There is no commonly accepted definition of what is system resilience though more and more people are talking about it. This project aims to develop a set of methods for measuring system resilience and predicting the system behaviors under disasters, as well as enhancing system resilience in average and worst cases respectively.

Info-

Communications

13-2 Xiao Gaoxi Assoc Prof egxxiao@ntu.edu.sg Title: Coevolution of opinions and connections in complex social networks Abstract: In this project, we shall study on the complex dynamics of the co-evolution of opinions and their underlying social networks. Benefiting from the latest developments in complex systems and multi-agent systems, we shall propose new models and novel analyses that will provide useful insights into the interesting co-evolution of social opinions and social networks.

Info-

Communications

13-3 Xiao Gaoxi Assoc Prof egxxiao@ntu.edu.sg Title: Control and controllability of complex networks and applications Abstract: In this project, we shall study on the control and controllability problems for complex systems and their applications. We shall investigate the possibility of developing new distributed, fault-tolerant methods to achieve effective, robust and scalable control of various complex systems.

Info-Communications

14-1 Yuan Junsong Assoc Prof jsyuan@ntu.edu.sg Title: Understanding human interaction in RGB-D videos

Abstract: Understanding human behaviors in real environments is one of the

most pressing challenges to human-centered computing. Because nobody

exists in a vacuum, the constant interactions among humans and those between

humans and surrounding objects not only capture what we do, but also reveal

our social sphere and who we are. Therefore, the ability to instantly detect and

recognize these interactions is crucial to the creation of novel computing

platforms that facilitate productive human-computer integration.

This project targets at recognizing human-human interactions, e.g., hand waving, using RGB-D sensor, e.g., Microsoft XBox Kinect. The student will have opportunity to collaborate with leading researchers at Microsoft Research Redmond, USA.

Info-

Communications

14-2 Yuan Junsong Assoc Prof jsyuan@ntu.edu.sg Title: Large-Scale Video Analytics and Search Abstract: This project will work on large-scale video content analysis and search, such as video anomaly detection and human activity detection.

Info-

Communications

15-1 Tang Yi Asst Prof yitang@ntu.edu.sg Title: Hierarchical control strategies of distributed energy storage systems for intermittency management Abstract: In order to reduce carbon footprint and combat global climate change, renewable energy sources (RESs) such as photovoltaic and wind power are increasingly penetrated into modern power grids. However, the intermittent nature of RESs may cause highly variable and pulsed output power that can greatly threaten the stability and security of power grids. Implementing grid-scale distributed energy storage systems (DESSs) could be an effective way to manage the intermittency of RESs and minimize their impact to the power grid. In this PhD project, hierarchical control strategies will be studied to optimize the performances of DESSs in terms of efficiency, reliability, and cost and meanwhile ensuring power grid resilience. The hierarchical control should include a distributed controller implemented in each DESS for fast response power control as well as a higher level centralized controller for grid-wide aggregation of multiple DESSs. RES and DESS models will be built in simulations along with the developed control algorithms. The proposed hierarchical control will also be verified in a laboratory micro grid test rig equipped with state-of-the-art power electronics facilities.

Electrical &

Systems

16-1 Wong Kin Shun, Terence

Assoc Prof ekswong@ntu.edu.sg Title: Thin film copper oxide heterojunction solar cell with plasmonic nanostructures Abstract: Copper oxide is a promising semiconductor material for photovoltaics because of the ease of deposition, low cost and abundance of copper and oxygen. It is also unique in that it exists in two crystalline forms (cuprous and cupric oxide) with different band gaps that allows fabrication of heterojunction devices from the same elements. Despite this, current copper oxide PV devices have low efficiency. In this project, a magnetron sputtering method will first be used to deposit cupric oxide and the mechanism of p-type doping will be investigated by electrical characterization. Heterojunction PV devices will be fabricated using both n-type Si and transparent conducting oxide substrates. The PV performance will be studied using I-V and external quantum efficiency measurements. In order to further enhance the light absorption, light trapping by incorporated plasmonic nanostructures will be studied. Both metallic nanoparticles with surface plasmon resonance and grating structure with surface plasmon polariton will be investigated by electromagnetic simulation and experiment.

Electronics

17-1 Fan Weijun Assoc Prof ewjfan@ntu.edu.sg Title: Fabrication and PL/PLE study of Ge-on-Si photonic materials Abstract: The impressive advances in Si-based microelectronics have continuously stimulated intense research efforts to develop optoelectronic solutions that can be integrated with Si technology. Recent research results show that Ge-on-Si is a promising candidate for the Si based laser diode potentially used in OEIC. In this project, we will use spurting method to deposit Ge-on-Si material and do post annealing to improve the material's quality. And use PL and PLE to investigate the materails' optical properties.

Electronics

17-2 Fan Weijun Assoc Prof ewjfan@ntu.edu.sg Title: Design of tensile strained Ge-on-Si laser Abstract: The impressive advances in Si-based microelectronics have continuously stimulated intense research efforts to develop optoelectronic solutions that can be integrated with Si technology. However, Si and Ge are indirect band gap semiconductors, which hinder their application to active devices in optoelectronic area. Several methods have been adopted to obtain Si-based optically active materials, such as exploiting erbium doping, nano-structure materials, hybrid III- V on Si systems, etc. Recently, Liu et. al. reported a novel tensile-strained Ge-on-Si laser operating at room temperature. To obtain efficient light emission from the direct gap transition of Ge, heavily n-type doping has been combined with 0.2-0.3% tensile strain in Ge. In this project, we will develop a method to simulate such type laser to investigate the strain and doping effect.

Electronics

18-1 Jiang Xudong Assoc Prof exdjiang@ntu.edu.sg Title: Machine learning based feature extraction from image and audio signal Abstract: Feature extraction takes a key role in the image and audio signal recognition. Yet there lacks effective techniques to extract discriminative and reliable features from image and audio signal because we have very limited expert knowledge about these features. Machine learning from database is a solution. However, how to make the learning results from a specific database general to the whole population is a challenging research issue worth to be investigated. Project Outline: Study the traditional techniques in feature extraction from image and audio signal; Study various machine learning approaches in feature extraction and dimensionality reduction; Explore the limitations and problems of the state- of-the-art technologies in these two areas; Develop robust new approaches to solve generalization problem of the machine learning in feature extraction. Evaluate and apply the developed approaches on the image object detection, recognition and speech recognition.

18-2 Jiang Xudong Assoc Prof exdjiang@ntu.edu.sg Title: High-dimensional, Incomplete And Unbalanced Data Analysis Abstract: In many real applications such as visual object detection and recognition, bioinformatics, and data mining, high data dimensionality imposes great burdens on the robust and accurate recognition due to insufficient knowledge about the data population and limited number of training samples. Incomplete data and/or unbalanced data make the knowledge discovery from the data even more difficult. They often cause biased estimation. While there are some techniques to handle the issues of high dimensionality of the data, problems of incomplete data and/or unbalanced data are new, which are very challenging and not well studied. This project aims at solving these challenging problems by generate novel techniques in machine learning, statistical estimation and pattern recognition.

Info-

Communications

18-3 Jiang Xudong Assoc Prof exdjiang@ntu.edu.sg Title: Sparse Representation and Dictionary Learning for Computer Vision Abstract: Sparse signal representation has proven to be an extremely powerful tool for acquiring, representing, and compressing high-dimensional signals. This success is mainly due to the fact that important classes of signals such as audio and images have naturally sparse representations with respect to fixed bases. In computer vision, we are often more interested in the content or semantics of an image rather than a compact, high-fidelity representation. Representing a signal involves the choice of a dictionary, which is the set of elementary signals used to decompose the signal. When the dictionary forms a basis, every signal is uniquely represented as the linear combination of the dictionary atoms. This project aims at solving difficult computer vision problems through the sparse representation of images based on proper learnt dictionary.

Info-

Communications

19-1 Tay Beng Kang Prof ebktay@ntu.edu.sg Title: Carbon Nanotubes Arrays for Field Emission Applications Abstract: Aim of the project

• Develop field-emission cathodes technology based on carbon nanotubes array

• Investigate the interface between carbon nanotubes array and substrate by using metal silicides as a transition layer

Proposal and its Significances: With the rapid development of communication and information technology, emerge a task of creating of electronic active devices, capable to operate at frequencies of the order of 1012 Hz. Unfortunately, due to several physical phenomena in semiconductors, (e.g., saturation, drift velocity and accumulation of minority carriers) solutions of these problems is challenging. Carbon nanotubes are a choice for field emission cathodes due to their unique combination of electrical, chemical, optical, thermal and mechanical properties. Despite the relatively high work function (about 4.7 eV), the important properties of carbon nanotubes for use as field emission cathodes are high electrical conductivity and an unusually high emissivity thanks to their quasi-one-dimension structure and high aspect ratio. However, studies have shown that the electron emission threshold current is only 1 mA cm-2, before burn out. Investigation into the failure mechanism shows that the main cause of degradation is the peeling of carbon nanotubes from the substrate due to insufficient adhesion of the cathode structure to the initial substrate. To resolve this issue, the interface between CNT and the existing substrate must be investigate. The use of metal silicide is a proposed to improve adhesion of carbon nanotubes to improve the threshold current. In this way, by resolving the problem of adhesion will open the way to a massive use of carbon nanotube based field emission cathodes with field-emission current densities up to tens of A/cm2 for a wide range of instruments and devices of micro-and nano-electronics.

Electronics

19-2 Tay Beng Kang Prof ebktay@ntu.edu.sg Title: Synthesis of carbon nanotubes and carbon hybrids nanostructures Abstract: Aim of the project

• Synthesis of arrays of vertically and horizontally aligned CNTs by the CVD method with a localized and volatile catalyst to achieve high electrical conductivity, optical transparency, as well as high emission properties.

• Investigate the key parameters for influencing the growth of CNTs, and hybrid nanostructures

• Development of physical and chemical models for the growth process of hybrid nanostructures Proposal and its Significances:

Carbon nanotubes possess many interesting and excellent properties for various applications. However, to achieve carbon nanotubes growth in the vertical and horizontal directions is challenging. One solution is to incorporate carbon nanotubes with different carbon families such as graphene to form carbon hybrids nanostructures. The growths of hybrids nanotubes have been successfully demonstrated, but the physics for the growth process are still unclear. It is therefore necessary to investigate the growth of carbon hybrids nanostructures to come up with physical and chemical growth models to create many other interesting nanostructures, and even on substrates such as metal or metal silicides. These hybrids nanostructures will lead to possible application in field emission, high-efficiency functional layers of organic solar cells and solar cell applications, as well as supercapacitors.

Electronics

20-1 Li Kwok Hung Assoc Prof ekhli@ntu.edu.sg Title: Optimizing Traffic Management of Heterogeneous Wireless Networks Abstract: A heterogeneous wireless network consists of devices using various radio access technology. One popular scenario is the inclusion of pico-cell and femto-cell networks within the traditional macro-cell networks. This type of networks is expected to be deployed in the next decade. The mixture of different devices leads to new challenges. There are many interesting issues still to be solved in heterogeneous wireless network such as interference management, dynamic resource allocation and green wireless transmission. The concept of heterogeneous wireless networks also opens up new research possibilities such as efficient and optimized traffic management for individual users to increase overall network performance, and application in the new "Internet of Things" paradigm. The research will focus on solving problems related to heterogeneous wireless networks and also introducing innovations within this new framework to improve the technology overall.

Info-Communications

21-1 Ang Diing Shenp Assoc Prof edsang@ntu.edu.sg Title: Oxide resistive memory for universal memory application Abstract: The scaling of conventional DRAM and flash memory technologies are now facing very difficult challenges. Through the years, the basic memory cell has evolved into a very complex form which makes continued dimension scaling cost-ineffective. Stacking of memory chips is now being considered an as alternative to further enhance the memory density. At the same time, there has been a lot of attention on the development of an alternative memory technology based entirely on a different operating principle from the current charge based counterpart. Among the various candidates explored, the oxide-based resistive memory stands out prominently by virtue of its simple metal-insulator-metal structure, which lends itself readily to direct multi-level backend CMOS integration in the form of cross-bar memory arrays. The Ph.D. student will be involved in an on-going resistive memory research project focusing on mechanism and modeling study.

Electronics

21-2 Ang Diing Shenp Assoc Prof edsang@ntu.edu.sg Title: Bias-temperature instability of small area MOSFETs Abstract: With the traditional silicon dioxide being replaced by alternative high-k oxides, charge trapping has become a serious issue in advanced MOSFET devices since the latter are intrinsically more defective. Recent studies by our group have shown that the electronic properties of oxide defects may continuously change under electrical-cum-thermal stressing. In particular, it is shown that charged oxide defects that are able to relax initially would become more permanently charged as stressing progresses, indicating that some form of defect structural change has occurred. Fundamental knowledge on the electrical properties of oxide defects in relation to their atomic structure is, however, still very limited. The Ph.D. student will be involved in an on-going research project, focusing on detailed electrical characterization study of random charge trapping and emission in small area MOSFET devices.

Electronics

21-3 Ang Diing Shenp Assoc Prof edsang@ntu.edu.sg Title: Development and characterization of CMOS-compatible Gallium Nitride high electron mobility transistors Abstract: Gallium nitride (GaN), by virtue of its large bandgap energy , offers advantages such as improved thermal stability and breakdown over other III-V semiconductors and is an ideal choice for high-power device applications. Although Au-based GaN HEMT process is now relatively mature, a CMOS-compatible Au-free process is still lacking. Successful development of the latter would unleash the full potential of the GaN-on-Si technology. The Ph.D. student will join an on-going process development project focusing on CMOS compatible contacts for GaN-on-Si HEMT devices. Detailed electrical characterization study will also be carried out on the fabricated devices.

Electronics

22-1 Goh Wang Ling

Dr. Liu Xin (Co-

supervisor)

Assoc Prof

Principal

Investigator

in IME

EWLGOH@ntu.edu.sg

liux@ime.a-star.edu.sg

Title: Reconfigurable Radio Baseband for Wireless Communication Systems

Abstract: During this research, we plan to develop an innovative reconfigurable

hardware platform for integrating multiple wireless communication baseband

protocols. In this platform, reconfigurable wireless signal processing modules

will be developed. A central control module is embedded to dynamically select

and configure the suitable signal processing modules to build up different

baseband structures. The parallelism of wireless signal processing will be

explored to maximize the throughput. Furthermore, the circuit-level innovation

will also be performed to further reduce power consumption while achieving

satisfied performance during ASIC implementation. The proposed hardware

platform is expected to support numerous major wireless protocols (e.g., WiFi,

Bluetooth, ZigBee, WBAN, UWB, etc.) which are normally utilized for

biomedical/healthcare related applications.

Electronics and Info-

Communications

22-2 Goh Wang Ling

Dr. Liu Xin (Co-

supervisor)

Assoc Prof

Principal

Investigator

in IME

EWLGOH@ntu.edu.sg

liux@ime.a-star.edu.sg

Title: Energy-Efficient and High-Throughput Signal Processing Hardware

Platform

Abstract: High throughput signal processing (e.g. video/Image processing)

requires intensive computation over large amounts of data, resulting in high

computation power and long processing time. Therefore, how to reduce the

overall computational complexity while maintaining the required performance

is challenging for efficient algorithm and hardware development. To overcome

it, we will develop the highly efficient signal processing hardware platform to

achieve ultra-low energy consumption as well as the satisfying performance.

To achieve this objective, the design efforts should be contributed to different

levels of design hierarchy: (1). Signal processing algorithm and hardware co-

development & co-optimization to achieve high efficiency; (2). Advanced

hardware architecture development to achieve high throughput with low

operation frequency, and to support reconfigurable/multi-mode signal

processing; (3). Energy-efficient architecture development to achieve high

energy efficiency; (4). Low-voltage operation circuit development to further

significantly reduce the power consumption.

Electronics and Info-

Communications

23-1 Soong Boon Hee Assoc Prof

ebhsoong@ntu.edu.sg Title: Network Optimization for interference Management for Heterogenous Cognitive Networks. Abstract: Over recent years, there has been a systematic increase of the requirements for the wireless resources requested by the mobile users. This has led to the increasing deployment of dedicated small-cells, where the considered small geographical area is served by low-range access points (or small base stations) creating a heterogeneous deployment hese deployments allow significant capacity enhancements and better coverage conditions that can be particularly beneficial for enhancing the bit rates of the users (spectral efficiency) that are located at the edges of the macrocells. Such advanced topologies composed by multiple cell sizes and involving the combination of different radio access technologies are usually known as heterogeneous networks or simply as HetNets. While some of the small-cells devices are deployed and installed by the operators e.g. in the street infrastructure, others (e.g. femtocells) are installed directly by the end-users offering portability and exclusive access to the spectrum within the user premises. On the other hand significant reduction of the cell radius results immediately in transmit power decrease as well as in creating of high potential for smart and effective resource and interference management to increase the system capacity. Moreover, the application of various wireless technologies used by the end users for spectrum access provides to the cellular network operators attractive opportunity for efficient traffic offloading to e.g. WiFi networks. Several research problems for this research work involves to for these heterogeous networks i.e. cognitive radio technologies for small-cells, Interference management and mitigation issue and Game theoretic algorithms management of dynamic spectrum allocation. Students should have a good background in research and programming.

Info-Communications

23-2 Soong Boon Hee Assoc Prof

ebhsoong@ntu.edu.sg Title: Design of Ambient Wireless Sensor Networks Abstract : Recent advances in hardware and wireless technology bring us the phenonmenal reality of accesses information anywhere, anytime through the collection of wireless sensor nodes (WSNs), RFID tags that forms the collection of Internet of Things. These networks are form by ad hoc sensor nodes deployed in an fashion in our environment for physical sensing and monitoring purposes to achieve a functional objectives. There are numerous applications for these smart sensor enabled devices with RF enable wireless communication capabilities that would help connect a large number of measurement points at low cost without the need for cabling so that conducting measurement e.g. in unsafe or harsh environment is of special interest. The research would involve the design and development of wireless sensor interfaces that would be helpful for the following technologies e.g. wireless USB, health monitoring, location tracking and surveillance. This

would be extended to multiple sensors that enable fusion of information and

processing. The scope of research include the following (1) Study Ambient

Wireless Sensor Systems (2) Design of DSP algorithms in embedded systems,

data management and storage, diagnostic decision making. Students should

have a good background in research and programming.

Info-Communications