January 8, 2018 8:45～10:15 IB015

13th Semiconductor ElectronicsProfessor Hiroshi AMANO

IMaSS, CIRFEamano@nuee.nagoya-u.ac.jp

Chapter Dates Contents1 October 15, 2018 Introduction, Wave nature of light, Reflectivity of metals and dielectrics2 October 22 Dielectric waveguide and optical fibers3 October 29 Quantum Mechanics, Band structure4 November 5 Electrical statistics in a semiconductor, Electronic defect states5 November 12 Home Work6 November 19 Transport7 November 26 pn junction 8 November 29 Midterm Examination9 December 3 Heterostructures

10 December 10 Direct transition, Indirect transition, Light-to-electricity conversion11 December 17 Solar cells12 December 26 Light Emitting Diodes13 January 8, 2019 Light Emitting Diodes and Laser diodes

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http://www.gijyutu.com/kyouzai/mokei/ohki2/light.htmhttp://kagakukan.toshiba.co.jp/history/1goki/1940fluorescent.htmlhttp://www.pawanavi.com/topics/2002/11/06/http://www.audio-q.com/tyuumon.htm

～19C fire 1st generation

1878 incandescent lamp(Long history, Joseph Swan,UK, Thomas Edison, USA) 2nd generation

1934 Fluorescent lamp(Long history, 1926 Jacques RislerFrance, George Inman, USA)3rd generation

1962 Commercial LED(Long history, 1907 Henry J. Round,

UK, 1927 Oleg Losev, Russia) 4th generation

Chemical reaction

Blackbody emission(early stage of quantum mechanics)

Energy transfer(quantum mechanics)

Solid state lighting

History of artificial lighting

Dec.13, 2014 Luciaball

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Operating principle of incandescent lamp

3000℃

http://page.cextension.jp/c3079/pageview/pdf/0310.pdf http://lamp1.com/product/category/denkyu/クリア電球/110v_c

Blackbody spectrum

＊Efficient in IR region Efficiency in visible region <20 lm/W

＊Short lifetime ＊Perfect color rendering

W filament Light

Light

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Operating principle of fluorescent lamp

http://www.jelma.or.jp/05tisiki/pdf/guide_flu_02.pdf

λ=253.8nmStokes shift

loss

Discharge

Mercury (Hg)

＊Efficiency is higher than that of incandescent lamp, but it is limited by Stokes shift loss＜120 lm/W＊Lifetime is limited by ion bombardment. ＊Hg is inevitable.

Electron

Filament (electrode)

Phosphor

Visible

Glass Metal cap

Q:How much about the Stokes shift loss when DUV photon with λ=253.4 nm transfer anenergy to red photon with λ=650.0 nm ?

%61650.0

2534.01 =−4/43

＋＋＋＋＋＋＋

＋＋

＋＋＋

ーー ー ーー ーーー ー ーー ー

ー ーー ーー ー

Electron flow

Conduction band minimum

Valence band maximum

N-clad P-clad

Photon

Hole flow

Active layer

Band gap N-electrode

p-electrode

Elec

tron

ener

gy

Operating principle of LED

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History of the development of LED Haitz’s law

R. Haitz and J. Y. Tsao, phys. stat. sol.(a)208(2011)17

1962 N. Holonyak Jr., GaAsP red LD

1971 J. Pankove, GaN MIS LED

InGaN blue LED+ phosphor

1952 H. Welker, GaAs, GaP

1968 RCA LCD

1974 GaP:N Green

1981 GaAsP:N Yellow

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1989 1998 1991 1999mova P

1991 ReleasedWebsite : DOCOMO CS Tohoku, INC.

Quoted from the history of the mobile phonehttp://www.docomo-cs-

tohoku.co.jp/museum/tanmatsu/p.html

Digital mova F502i HYPER1999 Released

Website : DOCOMO CS Tohoku, INC.Quoted from the history

of the mobile phonehttp://www.docomo-cs-

tohoku.co.jp/museum/tanmatsu/f502i.html

GAME BOY1989 Released

Photo ： Nintendo Co., Ltd.

GAME BOY COLOR1998 Released

Photo ： Nintendo Co., Ltd.

How blue LED change our lives?

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March 11, 2011 Great Earthquake attacked East Japan

Nuclear Thermal 87.8%

CO2 emission

LNG

Coal

Oil

Electricity generation and CO2 emission in Japan 2015/11/26 Report

How InGaN LEDs contribute to saving energy and environment ?

×100Mt-CO2×100M KWh

3.58

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U.S. DOE Energy Savings Potential of Solid-State Lighting in General Illumination Applications, Jan.2012

Totalconsumption4273 TWh

297/4273～7％

How InGaN LEDs contribute to saving energy in the US ?

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Year

LED lighting Other lighting LED ratio×1000

Data from Fuji Chimera Research Institute, Inc.,2014 LED Related Market Survey

In Japan, we can reduce total electricity consumption by about7% （=1,000,000,000,000 JP Yen） by 2020.

Forecast of LED lightings in Japan

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New industrial applications of LEDs

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Plant factory Medical Sterilization Fishery

Plant factory

Fishery

Sterilization

Medical

New industrial applications of LEDs

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http://www.sc.fukuoka-u.ac.jp/~bc1/Biochem/photosyn.htm

http://www.amazon.co.jp/植物育成-水耕栽培などに225球使用！15W強力植物育成LED照明-低消費電力で長寿命で明るい照明-a145-赤、青（植物育成仕様）/dp/B0042NV9YM

Plant factory

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A blue-shifted light-driven proton pump for neural silencing

Yuki Suto, Ayako Okazaki, Hikaru Ono, JinYagasaki, Seiya Sugo, Motoshi Kamiya,Louisa Reissig, Keiichi Inoue, Kunio Ihara,Hideki Kandori, Shin Takagi and ShigehikoHayashi

http://www.bio.nagoya-u.ac.jp/paper/2013-21/15.htmlJBC Papers in Press. Published on May 28, 2013 as Manuscript M113.475533The latest version is at http://www.jbc.org/cgi/doi/10.1074/jbc.M113.475533

Medical application

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http://www.33rdsquare.com/2013/04/scientists-develop-tiny-implantable-led.html

Washington University School of Medicine in St. Louis and the University of Illinois at Urbana-ChampaignRead more: http://www.33rdsquare.com/2013/04/scientists-develop-tiny-implantable-led.html#ixzz2u7anAwHi

Science 12 April 2013:Vol. 340 no. 6129 pp. 211-216

Photon drug, LED drug = clean

Medical application

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UnicefWorld Health Organization,Progress on Drinking Water and Sanitation2015 Update

Global warming causes increase of bacterium and virusin drinking water.

663 Million people

2.4 Billion people

do not use an improved sanitation facility.

lack access to improved drinking water sources.

People who cannot access to safe water

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●Effect of UV irradiationDNA of bacterium is damaged. ⇒ They lose proliferating ability.

260-270nm

Transparencyof UV lightIntensity Exposure

time weakness× × × ×

Heat sink

UV LEDFluorocarbon(UV reflector)

Copyright © 2017 NIKKISO CO., LTD .All rights reserved.

Water inWater out

Five factors influencing the performance of water purification

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1 1×0.951×0.95×0.95

0Position

Intensity

1 cm 2 cm N cm

1×0.95N

Transparency 1cm 2cm 5cm 10cm 20cm95% 95% 90% 77% 60% 54%90% 90% 81% 59% 35% 28%70% 70% 49% 17% 3% 1%

260-270nm

Transparencyof UV lightIntensity Exposure

time weakness× × × ×

Purification of waste water is difficult.

Copyright © 2017 NIKKISO CO., LTD .All rights reserved.

Transparency

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medical

Grass bacillus

Pseudo monas aeruginosa

In water

Colon bacillus

Cryptosporidium

Legionella

Infection

Adenovirus

Influenza virus

Norovirus

Strong

Strong

260-270nm

Transparencyof UV lightIntensity Exposure

time weakness× × × ×

Weakness of bacterium and virus

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260-270nm

Transparencyof UV lightIntensity Exposure

time weakness× × × ×

(LED intensity)×(Absorption of DNA)

Colon bacillus MS2 Phage

Wavelength [nm] Inac

tivat

ion

effic

ienc

y

Copyright © 2017 NIKKISO CO., LTD .All rights reserved.

Absorption of DNA

Intensity of LEDs

Wavelength [nm] Inac

tivat

ion

effic

ienc

y

Inte

nsity

ofLE

Ds

Effective wavelength

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資料提供：

LEDHg lamp

Operation time (h)

Inte

nsity

(%)

conventional lamp < 2,000 hours (3months)

JWRC: Japan Water Research Center

①World’s biggest! Water supply system using DUV LEDs1,200 m3/day for 3,500 people (JWRC certificate)

② High dose >30 mJ/cm2

Three times higher than 99.9% damagingcryptosporidium in water

③ Long Lifetime 45,000 hours (>5 years）cf. conventional lamp < 2,000 hours

○ Compact ○ Hg free

Long lifetime

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©2008 Beams Inc. Photolithography

© 2016 FESPA Resin cure

Paper money discrimination

Dermatology

UV curing© 2001 MIMAKI ENGINEERING CO., LTD

Sterilizationhttp://news.livedoor.com/article/detail/10208189/

Water purification

10 L/m

2 L/m

120 L/m

Expansion of applications of DUV LEDs

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http://gajethouse.blog3.fc2.com/blog-entry-791.html

http://blogs.yahoo.co.jp/fpdxw092/61943354.html

http://dankai-hiroba.cocolog-nifty.com/blog/2007/07/post_5274.html

LED catalogue

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http://www.futurelightingsolutions.com/en/technologies/product-lines/Documents/japanese_literature/luxeon_a_jp.pdf

From the LED catalog

CCT ?CRI ?lm/W ?

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ocusPlanckianL

http://en.wikipedia.org/wiki/Planckian_locus

Homes in the U.S.2800 K to 3000 K

Office in the U.S. 4200 K

Home in Japan 5000 K

Correlated color temperature

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1cd1sr

lm555nm683[lm/W]

500 600 700400

Wavelength [nm]

500

1.0

0.1

0.01

V’(λ)

450[nm]22[lm/W]

520[nm]410[lm/W]

650[nm]82[lm/W]

cd: The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 Hz and that has a radiant intensity in that direction of 1/683 Watt per steradian.

The lumen is defined in relation to the candera as1 lm = 1 cd・sr

lm/W

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How human identify color ?

http://www.kiriya-chem.co.jp/q&a/q52.html

Retina

Eye Optic nerve

Photon

Human

Bird(starling)

Spectral sensitivity

Wavelength

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html#c4

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8

RR.I.R.C

8

1ii

a

∑===

ii E6.4100R ∆×−=

http://en.wikipedia.org/wiki/Color_rendering_index

01

15

08

References

Color rendering index (CRI) Ra=Average (R1～R8)

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© ResearchGate 2018. All rights reserved.

lm/W and CRI

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Copyright (C) 2010 soujitu-lamp. All Rights Reserved.

Low CRI

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Data from NIST

CCT(K) CRI LER(lm/W)3-LED 1

(457/540/605)3300 80 409

4-LED 1(461/527/586/637)

3300 97 361

Ref. B-LED + YAG 6810 81 294

Ideal light source

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Principle of laser diode

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Semiconductor laser diode and gain

https://www.researchgate.net/publication/253318527_The_Development_of_Concepts_in_Light-Emitting_Devices/figures?lo=1

Figure 1. Evolution of semiconductor laser current thresh

A/cm2

Figure 2. (a) schematics of a semiconductor laser (b) balance equation for an optical wave undergoing a roundtrip in the cavity. Figure 3. Schematics of gain

formation in a semiconductor: (a) and (b) absorption and stimulated emission transitions under weak (a) and strong (b) injection Note the position of the quasi-Fermi levels EF c and EF v (c) absorption and gain under increasing excitation (from Casey and Panish 6] ).

33/43

2D and 3D laser diode

Figure 5: Schematics of the gain formation in 3D bulk DH active material (top) and in a 2D QW material (bottom). Due to the smaller density of states in 2D the transparency current I0 is diminished. Due to the square density of states, a given number of injected carriers is more eecient to create gain in the 2D QW, which translates into a steeper gain-current curve.

https://www.researchgate.net/publication/253318527_The_Development_of_Concepts_in_Light-Emitting_Devices/figures?lo=1

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GRIN-SCH and SCH laser diode

Figure 6. Quantum well laser structures and current-gain curves. (a): Graded-index separate confinement heterostructure laser (GRIN-SCH)) (b): separate confinement heterostructure (SCH) single quantum well laser (c) multiple quantum well (MQW) laserr (d) schematics of the gain-current curve for a single QW GRIN-SCH laser and a 800 A active-layer DH laser. Note the large difference in transparency currents J0, the curvature and saturation of the QW gain curve (due to the 2D DOS, see text) and a ¥desaturation" of the gain once an excited level (Ee2) starts to be populated.

https://www.researchgate.net/publication/253318527_The_Development_of_Concepts_in_Light-Emitting_Devices/figures?lo=1

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Quantum dot laser diode

Figure 8. Schematics of quantization in electron quantum boxes or in optical microcavities.

https://www.researchgate.net/publication/253318527_The_Development_of_Concepts_in_Light-Emitting_Devices/figures?lo=1

36/43

Threshold current density

Figure 9. Comparison of gain formation in bulk QW, Quantum Wire (QWW) and Quantum Box (QB) materials, and corresponding gain-current curves (from Asada, 1986).

https://www.researchgate.net/publication/253318527_The_Development_of_Concepts_in_Light-Emitting_Devices/figures?lo=1

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Gain in a semiconductors 𝛼𝛼= 𝑊𝑊abs

v� nph= 𝜋𝜋e2

𝜖𝜖m021v𝜔𝜔

(a � p)cv 2Ncv(ħ𝜔𝜔)

𝑔𝑔(ħ𝜔𝜔)= 𝜋𝜋e2ħ𝑛𝑛𝑟𝑟𝑐𝑐m0

2𝜖𝜖0

1ħ𝜔𝜔

(a � p)cv 2Ncv(ħ𝜔𝜔) fc 𝐸𝐸𝑒𝑒 − fv 𝐸𝐸ℎ

If positive, there is a gain.

)(Ecρ

)(Evρ

Ec

Ev

pF

nF EE =

fc~0

fv~1

intrinsic

)(Ecρ

)(Evρ

Ec

Ev

pF

nF EE =

fc~1

fv~1

n++ equilibriumfc-fv~－1 fc-fv~0

)(Ecρ

)(Evρ

Ec

Ev

nFE

fc＞0.5fv＜0.5

Highly excited

pFE

fc-fv>0

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Transparency condition

gpF

nF EEE =−Transparency condition and the effective masses of conduction band electron and valence

band hole

)(Ecρ

)(Evρ

Ec

Ev

nFE

fv

fc

pFE

mv=5mc

)(Ecρ

)(Evρ

Ec

Ev

nFE

fv

fc

pFE

mv=mc

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Density of electron–hole pairs at which material becomes transparent

GaAs In0.5Ga0.5P GaN

Electron effective mass me/m0 0.067 0.105 0.2

Light hole mlh/m0 0.082 0.14 0.33

Heavy hole mhh/m0 0.45 0.48 1.66

Valence band state density effectivemass mh/m0

0.47 0.53 1.76

Transparency density N0/cm3 1.3*1018 2.3*1018 8.4*1018

0* NqdJs

th τ=Threshold current density τs：radiative recombination time

GaAs：2~3nsecGaN：2~4nsec

GaAs : 0.16～0.4 KA/cm2

GaN : 1～2.4 KA/cm2

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Gain spectrum of actual LD

Material gainLD gain

Q：What is the difference ofbroken line and solid lime ?

Q: Why are theyso different ?

41/43

Material gain and modal gain

)1ln(21

21RRLgG ithth +=Γ= α

Internal loss：

FP reflectivityCavity length

pgfcsci αααα )1( Γ−+Γ+=

Free carrier absorptionLoss in cladScattering loss

Current density and gain

Threshold current density Jth ?

10

2121 )1ln( JdJ

RRdJ Lith ++

+

Γ=

ηα

η

η：internal quantum efficiencyJ0：Threshold current density at which material becomes transparentd：active layer thicknessJ1:reactive current consumed by Auger recombination or interface roughness

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Confinement factor Γ

http://www.semiconductor-today.com/news_items/2009/DEC/UCSB_311209.htm

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https://ecee.colorado.edu/~bart/book/book/chapter4/ch4_10.htm