Post on 28-Nov-2021
AFM of hBN surface
Dry Transfer and Characterization of GrapheneNanoribbons
Dry Transfer Process
Acknowledgments
Background
Bryan Manuele1, Juan Pablo Llinas2, Shuang Wu2, Kyunghoon Lee2, Jeongmin Hong, Jeffrey Bokor2
1. Foothill Community College, 2. University of California, Berkeley
The goal of the dry transfer process is to transfer a hexagonal Boron Nitride flakes onto any arbitrary substrate
z
1. Prepare a Dry Transfer Stamp (PPC on PMDA on Glass)2. Line up the dry transfer stamp with the target material, and anneal the
surface till the material is securely on the stamp3. Line up the dry transfer stamp with the target substrate, and anneal the
surface till the material is securely deposited onto the substrate
Special Thanks to:Prof. Jeff Bokor,
Juan Pablo Llinas,Dr. Shuang Wu,
Dr. Kyunghoon Lee,Dr. Jeongmin Hong.
Graphene Nanoribbon Platform Atomic Force Microscopy
Hexagonal Boron-Nitride
Future Research
Hexagonal Boron Nitride (hBN) is a suitable insulating substrate to characterize Graphene nanoribbons on due to its atomic smoothness (root mean square roughness of only 1.5 Å).
2um
100nm
The lattice structure of hBN also matches that of graphene, and has a lattice constant difference of only 1.8%
Graphene on h-BN lattice
AFM of two adjacent h-BN flakes
Summary
Scanning Tunnel Microscopy (STM) of 13A wide Graphene Nanoribbons before
transfer1
We develop a transfer process to deposit hexagonal boron nitride flakes onto any arbitrary substrate, and characterized graphene nanoribbons by preforming atomic force microscopy on a GNR/hBN heterostructure.
Graphene Nanoribbons (GNRs) with atomically precise <2 nm widths have potential applications in ultra-scaled transistor devices due to their semiconducting properties, but have yet to be characterized after transfer.
13A Graphene Nanoribbons before transfer Imaged using Atomic Force Microscopy
GNRs are challenging to image after transfer because of their one Angstrom height profile. Roughness in the substrate underneath can cause the GNRs to appear undetectable.
Atomic Force Microscopyof silicon Dioxide
References
13A GNR
10Å
Graphene Nanoribbon Transistor devices imaged with AFM
AFM of Graphene Nanoribbons on h-BN
Hexagonal Boron Nitride and Sapphire are both atomically smooth and transparent. We chose to image the GNRs on a hBN / sapphire Heterostructure, because doing so allows us to take AFM and optical measurements of the GNRs,
Graphene Nanoribbon Field Effect Transistor that exhibitsswitching behaviour2
1. Yen -Chia Chen, et al., ACS Nano 7, 6123 (2013)2. Juan Pablo Llinas, et al., Short Channel Field Effect Transistors with 9 Atom an 13-Atom wide Graphene Nanoribbons3. Duoming Wang, et al., PRL 116, 126101 (2016)4. Abhisek Gupta, et al., Nanoscale 4, 6562-6567 (2014)
3nm
0nm
Transferring h-BN onto Sapphire
3nm
An atomically sharp tip on a cantilever taps along the surface of a substrate, resulting in a 2D plot of the height of the substrate.
AFM image of Tungsten
150nm
15nm
0nm
AFM Phase Image of Graphene Nanoribbons
10°
0°
AFM Amplitude Image ofGraphene Nanoribbons
5nm
0nm
Section graph of SiO2 substrate
Section graph of hBN / sapphire heterostructure
Optical image of the GNRson the hBN / Sapphire
heterostructure
By depositing the GNRs onto an hBN / Sapphire heterostructure, we were able to image the GNRs using Atomic Force Microscopy. Our results show that the GNRs transfer cleanly when deposited onto an arbitrary substrate.
Atomic Force Microscopy Schematic
Atomic Force Microscope
Graphic of Graphene Nanoribbons on a hBN / sapphire heterostructure
500 um
15nm
7nm
0 nm
Thermally Induced RotationIn Graphene3
Further research can be conducted in characterizing graphene nanoribbons. In the future, we plan to characterize them by measuring photoluminescence, and by observing thermally induced alignment in the GNRs.
Photoluminescence of GNRs of varying widths
1um
1um
400nm
20x
200nm
Support Information This work was funded by National Science Foundation Award ECCS-1461157 & ECCS-0939514