SEMICONDUCTOR QUANTUM WELL AND

QUANTUM DOT HETEROSTRUCTURES:

LASERS AND LIGHT EMITTING DIODES FOR

VISIBLE AND UV SPECTRAL REGION

G. P. Yablonskii

Stepanov Institute of Physics of Belarus Academy of SciencesLaboratory of Physics and Technique of SemiconductorsIndependence Ave. 68 Minsk BelarusE-mail: yablon@dragon.bas-net.by

INTERNATIONAL CONFERENCE ON PHYSICS OF LASER CRYSTALS - Radiation Processes in Nano and Bulk Materials

OUTLINE

1. HETEROSTRUCTURES: basic conception, history, materials, technologies

2. LASERS3. LIGHT EMITTING DIODES - LEDs4. ORGANIC LEDs5. ORIGINAL RESULTS

1. HETEROSTRUCTURES: basic conception, history,

materials, technologies

SOME BASIC DEFINITIONS:

Heterostructure: Crystal consisted of one ore more junctions between different semiconductors with different Eg, lattice constants, layer thikness Eg > 2 eV wide band-gap semiconductors

Design: Substrate + a sequence of thin layers

Potential well:

Active layer Ega < Egc of claddings (barriers) Band offset: ΔEv > 0, ΔEc < 0

Classical: Lxa «Ly, Lz, Lxa » λΒ = h/p,

Lxa » aB λΒ is the de Broglie wavelength of the carriers aB is the Bohr exciton radius

Quantum well:

Lxa « Ly, Lz and Lxa ~ λΒ, aB Quantum size effect:

the carrier movement in the x direction is quantized the carrier energy becomes definite discrete

Optical and carrier confinement due to ΔEg and Δnr Heterostructure types:

Single heterostructures Double heterostructures Single, double and multiple QWHs Separate confinement QWHs Graded-Index SCH

HETEROSTRUCTURES: HISTORY AND PROGRESS

GaAs BASED HETEROSTRUCTURES 1963 conception of double heterostructure lasers:

double injection, c&o confinement Alferov, KazarinovKroemer

1966 1967

GaAsP-lattice mismatched DH LDs, 77K AlGaAs-lattice matched heterostructures

Alferov et al. Rupprecht et al.

1969 AlGaAs-DH LD: Jthr=4300 A/cm2, RT, pulse, 770 nm, LED, transistors, solar sell elements

Alferov et al.

1970 AlGaAs LDs, CW, RT, Jthr=940 A/cm2

InGaAsP: from IR to visible

Alferov et al. Hayashi, Panish Alferov et al. Antipas et al.

1974 Quantum sized effect in GaAs/AlGaAs (multi) graded structure of kabs, hν = F(dw) Resonance tunneling

Dingle et al. Esaki, Chang, Tsu et al.

1975

First AlGaAs/GaAs MQW optically pumped laser, T = 15 K, hν = 1.53 eV

Van der Ziel, Dingle et al.

1978 AlGaAs/GaAs LD, RT, QUANTUM WELLJthr=3*103 A/cm2, λ = 800 − 840 nm

Dupius, Dapcus, Holonyak et al.

1980 QW heterostructures: transistors, Quantum Hall effect

Mimura et al. Klitzing et al.

1982 AlGaAs/GaAs GRINSH, Jthr=160 A/cm2 Tsang et al. 1983 GaAs/InGaAs strained LD, RT, CW Holonyak et al. 1996 1997

InGaAs/GaAs QDs LDs, RT, CW Jthr=97 A/cm2, P = 160 mW, hν = 1.3 eV

Bimberg, Park, Alferov et al,.

2000 InGaAs/GaAs QD transverse&VCSEL, λ =1.3 μm, J

ZnSe BASED HETEROSTRUCTURES

1990 p-ZnSe:N Park et al. 1991 ZnSe/ZnCdSe QW SCH LD, T = 77 K

λ = 510 nm Qiu et al. Haase et al.

1997 2000

RT, CW, t = 400 h, Jthr = 500 A/cm2, Ithr = 25-30 A, P = 20 mW

SONY Okuyama et al Landwehr

2000 ZnSe/CdSe QD lasers, RT, Ithr = 4 kW/cm2 Kopjev, Ivanov Alferov, Usikov et al.

2000 ZnSe “white” LED: blue LED+orange PL Blue-green-orange Mixed-Colour LEDs I = 20 mA – 2 mW, U = 2.7 V, t > 800 h Blue-red ZnSe/BeTe LEDs: - 1000 h

Sumimoto Ltd Reusher, Ivanov et al.

1994 1996

ZnSe based QWHs: Stark effect, self-electro-optics effects, bistable switchers, modulators

Ebeling, Gutovskii et al., Marquardt, Heuken et al. Cavenett et al.

1999 2001

ZnMgSSe/ZnSe. Theory: 2D e-h plasma band gap renormalisation, Auger effect in trions.

Poklonski et al.

1997 2000

ZnMgSSe/ZnSe SCH MQW OPL: Tmax=612 K, λ = 440–490 nm, Ithr=20 kW/cm2 Effect of inherent laser annealing

Yablonskii, Gurskii, Kalish, Heuken, Heime et al.

2003 ZnMgSSe/ZnCdSe quantum dot laser pumped by the GaN blue laser

Yablonskii, Gur-skii, Lutsenko, Ivanov, Heuken et al.

GaN BASED HETEROSTRUCTURES

1992 p-GaN:Mg e-beam annealing thermal annealing

Akasaki et al. Nakamura et al.

1994 1995 2000

InGaN/GaN QW LED, T = 300 K T ~ 5*104 h, T = 325 K, η = 16% Al(In)GaN/Al(In)GaN QW LED: V=2-8 V, 340 – 540 nm, I=0.2-20 A, P = 10 mW

Nakamura et al. Nichia, HP, Cree EMCOR,XEROX Otsuka et al.

1996 InGaN/GaN LD, T = 300 K, pulsed, λ =419 nm, U = 28 V, Jthr = 13 kA/cm2

Nakamura et al.

1998 2000

InGaN/GaN SCH LD, CW, RT, λ =410 nm, P = 2 mW (104 h), P=30 mW (150 h, 320 K) Jthr=3.6 kA/cm2, Ithr = 43 mA, Uthr= 4.3 V. 10 (30) mW, 60oC 2000 (500) h; P=40 mW

Nakamura et al.

2000 InGaN/GaN QW LD, T = 300 K, λ =450 nm (4.6 kA cm-2, 6.1 V), t = 200 h, P = 5 mW

Nakamura et al.

1997 2000

Al(In)Ga/AlGaN QD OPL T = 20 K, hν = 3.48 eV, Ithr = 0.75 MW/cm2 QD VCSE OPL (16 K, 3.02 eV, 1 MW/cm2)

Tanaka et al. Krestnikov et al.

AlGaN/GaN transistors: HEMT, MESFET, BJT, Eg = 3.4 eV, Ebd = 5 MV/cm, μ = 2000 cm2/Vs, fpgf=100 GHz, Tm =673 K, t>1000 h

1999 2001

Pt-GaN, Pt-AlGaN-HEMT transistors Gas (H2, CO, NO) sensing devices

Luther et al, Schalving et al.

19962000

Piezoelectric field up to 1 MV/cm2 in In(Al)GaN/GaN QWs, nscr > 1018 cm-3

Hangleiter et al. Bernardini et al. Chichibu et al.

1998 2000

InGaN/GaN QWs: UV laser assisted annealing, OPL λ = 450–470 nm, T > 300 K

Yablonskii, Lutsenko, Schineller, Heuken et al.

2002 InGaN/GaN true blue laser Yablonskii, Lutsenko, Gurskii, Heuken et al.

2002 InGaN/GaN/Si blue laser Yablonskii, Lutsenko, Gurskii, Heuken et al.

DENSITY OF STATES AND CARRIER DISTRIBUTION

Schematic drawing of density of states functions of structures withdifferent dimensionality for electrons (black lines). Schematic drawing

of occupied electron states under excitation (red lines)

Em

E vcvc 2232

,)0( , 2

)2()(

πρ

h=

∑ −=n

zz

vcvc nEEHL

mE )]([

)( 2

,)1( ,

hπρ

∑ −−= nl zyzyvc

vc nElEELLm

E ,

21

21 2 ,)2(

, )]()([1

)2(

)(π

ρh

∑ −−−=nlk

zyxzyx

vc nElEkEELLLE

, ,

)3( , )]()()([

1 )( δρ [1]

2

,

)1(

2 ⎟⎟⎠

⎞⎜⎜⎝

⎛=

xhen L

nm

E πh [2]

1 Y. Arakawa and H. Sakaki / Appl. Phys. Lett. 40 (11), 19822 B. Mroziewicz et al. / Physics of Semiconductor Lasers ( by PWN – Polish ScientificPublishers – Warszawa, 1991) p.180

STRUCTURE DESIGN AND CARRIERDISTRIBUTION

Schematic drawings of several QW laser structuresand associated energy levels and occupied electronstates under carrier injection[1].

1 С. Weisbuch / Journal of Crystal Growth 138 p.776-785, 1994

p n++++_

_ ___

+

E

E

x

FE

C

EV

+x

EC

EV

Fe F

h

Energy diagram

Main weak pointsStrong temperature dependence of laser thresholdHigh threshold current density (J>25x10 A/cmat Т=300 К)Low total quantum yield (2-3% at T=300 К);Cooling by liquid gases is necessaryShort lifetime (several hours at Т=300 К)

3 2

CLASSICAL HETEROSTRUCTURESFundamental physical phenomena:

a) - one-sided injection andsuperinjection;

b) - diffusion in built-inelectrcal field;

c) - electrical and opticalconfinement;

d) - effect of wide-gapwindow;

e) - diagonal tunneling overthe heterointerface.

Important features for technology: In principle, lattice-matched structures are necessary; For lattice matching, multicomponent solid solutions should be

used; In principle, epitaxial growth technology is necessary

Important consequences for application insemiconductor light emitting devices

Low threshold semiconductor laser diodes operating in CW regimeat room temperature (Jth∼103 A/сm2);

High-efficient LEDs

But: Threshold current is still high enough; Strong temperature dependence of threshold current

Zh.I.Alferov. Sov. Phys. Semicond, 1998, Vol. 32, №1, p.3-18.

Quantum Well HeterostructuresFundamental physical phenomena:

3.3 эВ

3.05 эВ

- two-dimentsional electrongas (2DEG);- step-like function ofdensity of states;- increasing exciton bindingenergy ⇒ their excistence atroom temperature ispossible;- effect of wide-gap window;- quantum Hall effect;- coherent growth ofstrained layerheterostructures;

Important features for technology:Lattice-matched structures are not always necessary;Suppression of misfit dislocation formation during growth;In principle, well-controlled epitaxial growth technology with lowgrowth rates is necessary (МВЕ, MOVPE), possibly with atomic layergrowth mode (АLE);

Important consequences for applications insemiconductor light emitting devices:

Lower threshold current density at room temperature (Jth∼100 A/сm2);Weaker temperature dependence Jth (Т); higher differential gain;High-efficiency LEDs and quantum cascade IR lasers;Lasers with superlattices in guiding layer ⇒ (Jth∼40 A/сm2);

(Zh.I.Alferov. Sov. Phys. Semicond, 1998, Vol. 32, №1, p.3-18).

SYSTEMS BASED ON QUANTUM DOTS (QD)Based on the self-organizationeffect of semiconductornanostructures in heteroepitaxialsystems

Minimum dimension of QD Dmin:

)(2 1min

2

*

2

QDEDm

Ee

C Δ≡=Δπh

Maximum dimension of QD

)(1 QDEkT ≤

FUNDAMENTAL PHYSICAL PHENOMENA: Zero-dimensional electron gas; Density of states is delta-function-like; Increasing exciton binding energy.

IMPORTANT FEATURES FOR TECHNOLOGY: Use of self-organization effects for growth; Lattice-mismatched layers of the structure are often

necessary; Epitaxial growth in V-riffles; High-resolution litography in combination with etching of QW

structures.

IMPORTANT CONSEQUENCES FOR APPLIATION INSEMICONDUCTOR DEVICES

Lover threshold current and higher differential gain; Тemperature stability of threshold current Discontinuous gain spectra ⇒ operation characteristics like

those of gas and solid-state lasers are possible; The possibility of creation of “single-electron” devices; The possibility of creation of “defect-free” devices

But: Technology is poorly developed, reproducibility problems

LASER THRESHOLD

Current density and gain:

)( ,322

2 ,

2

gmgm Eg

cEEden

Jηπ

γh

Δ= ,

⎟⎟⎠

⎞⎜⎜⎝

⎛ Δ−−

⋅⋅Δ

= ∫∞

kTFEEr

ErEEr

dEEr

m, gm, gsp

m, spsp

m, spsp

sp

exp1

1)()(

)()(

0

γ

Threshold condition:

⎟⎟⎠

⎞⎜⎜⎝

⎛+++Γ−+Γ==

21imax

1ln1)1(rrL

g csafcwafca ααααα

Optical confinement factor:

( )Γ =

+ ⋅⋅

−

dd

N dd

n n

a a

a

2

2 22

22 2

λπ

, d N d N da a b b= + , ( )n N d n N d n da a b b b= +0

Jthr = f(T):η)()( nsp

nthr edRJ = , ]3 0,[∈n

∫∞

=0

)( ,

)()( )),(,( dETEErR nvcn

spn

sp ρ

Results:

Fig. 1 Theoretical temperature sensitivity of LDs of the activelayers with various quantum confinementdimensionality [1]

1 Y. Arakawa and H. Sakaki Appl. Phys. Lett. 40 (11), 1982

Nitrides and IINitrides and II--VI VI -- possibilitiespossibilities

InstituteInstituteof Physics, of Physics, Minsk, Minsk, BelarusBelarus

• AlN - Eg ~ 6.2 eV, λ = 198 nm• GaN - Eg ~ 3.4 eV, λ = 364 nm• InN - recent data: Eg ~ 0.7 eV, λ ~ 1770 nm• Compounds based on:• AlN-AlGaN light emitting devices, lasers and

photodetectors for the far and near ultraviolet spectral region

• GaN-InGaN light emitting devices, lasers, photodetectorsfor the visible and near infrared spectral region

400300 500 600 700WAVELENGTH (nm)

3 2.53.5 2ENERGY (eV)

Ga(In,Al)As(P)615 nm LD CW608 nm LD pulsed586 nm opt. pump390-480 nm

LD CWLEDs:280-310 nm

up to 470-490 nmopt. pump

Ga(In,Al)Nup to 282 nmopt. pump

The green-yellow laser region is still not filled by III-Vs

MOVPE growth technologyMOVPE growth technology

Scheme of MOVPE grown

Substrate

Heating

Gases flow

Good facility for Good facility for mass productionmass production

MBE growth technologyMBE growth technology

Good facility for Good facility for growth controllable growth controllable monolayer and QDmonolayer and QD

2. LASERS

Laser Diodes

1. LASERS emit light from the edge

2. VCSELs - Vertical Cavity Surface Emitting Lasers

Vertical Cavity means that the cavity is perpendicular to the semiconductor wafer

Surface Emitting means that the light comes out from the surface of the wafer

AlGaN/AlInGaNMQWlasers:

λ=240 – 480 nm LD

OPL

415 nm LD:P = 1000 mWI = 1000 mAU = 12 Vτ = 200 nsF = 100 kHzTop = 400Ct = 1000 hPrice – 1300 EURGaAs – based lasers:λ = 0.6 – 49 μmPs= 16 W, Parray = 1-2 kW

Total laser market in 2006: $5.98B, Including LD – 59%.

Application of UV LDs and LEDs

Electron beam pumped lasers

Lebedev Physical Institute RASPrincipia LightWorks Inc, CA

CdSSe/CdSZnCdSe/ZnSSe/ZnSe

ZnSe/ZnMgSSe/GaAs

GaInP/(AlGa)InP

LIGHT EMITTING DIODES - LEDs

~50-300 нм p-GaN~5-30 нм p-(Al,Ga)N

1500-4000 нм n-GaN

3-50 nm GaN buffer

Al2O3

p-electrode

n-electrInGaN/GaN MQW

LED arrayLED arrayLED with LED with

transparent transparent contactcontact

LED structureLED structure

Parameters and pricesParameters and prices1. 1. WhiteWhite LuxeonLuxeon –– 600 600 mWmW, 1500 , 1500 mAmA, 10, 10--12 12 VV, 100000 , 100000 hh, 5 , 5 –– 6 6 EUROEURO2. 2. White on White on ZnSe ZnSe –– 11--2 2 EUROEURO3. 3. BlueBlue--yellowyellow, , мВтмВт, 20 , 20 мАмА, 1, 1--3 3 EUROEURO4. 380 4. 380 nmnm, 20 , 20 mAmA, 3, 3--5 5 mWmW5. 360 5. 360 nmnm, 20 , 20 mAmA,, 1 1 mWmW6. 255 6. 255 nmnm, 20 , 20 mAmA, 100 , 100 –– 200 200 μμWW 77. 210 nm, 0.02 . 210 nm, 0.02 μμWW, 25 V, , 25 V, AlN:Mg/AlN/AlN:SiAlN:Mg/AlN/AlN:SiСтоимостьСтоимость попо пп..пп. 4,5,6 . 4,5,6 –– отот 5 5 додо 500 500 ЕЕUROURO

Автомобильная техникаИнформационные дисплеи

Освещение

Подсветки

Другое

Сигнальныеустройства

LED market structure for 2005 - 2010

6%2%

14%

12%

14% 52%2005г.

11%13% 28%

34%13%

1%2010г.

2005г. – 4 Billion $. 2010г. – 8,2 Billion $.

Energy and funds saving1 TW-hour/year

10 B$/year

2

BBacklightingacklightingTV and displaysTV and displays

BBacklightingacklightingautomotiveautomotive

37

The Burj Al Arab, Dubai

BBacklightingacklightingbuildings andbuildings and constructionconstruction

Physical and technical problems

Lattice mismatch of layers and substrates (Al2O3, SiC, Si);GaN homoepitaxy;Piezo-fields, LiAlO2;In clusterization in InGaN:localized and delocalized states. Green and red spectral regions for InGaN QWs;UV light emitting devices based on

ORGANIC LEDs

The potential annual global sales of each type of organic semiconductor devices by 2020

Original results

Experimental setups

CRYOSTAT

CHOPPER

LOCK- INAMPLIFIER

PMT

XENONLAMP

MONOCHROMATOR

MO

NOC

HR

OM

ATOR

REFRIGERATOR

He-CdLASER

CHOPPER

LOCK - INAMPLIFIER

PD

MONOCHROMATOR

PD

HALOGEN,DEUTERIUM,OR XENON

LAMP

Photo- and electro-reflectance and absorptionexperimental setup

Photo-luminescence excitation experimental setup

Experimental setups

337 nm, 8 ns, f=1000 Hz

= 325 nm, cw

lt==410 - 500 nm, 10 ns, f=50 Hz

= 540, 360, 270 nm, 10 ns, f=50 Hz

Excitation sources

e-gun

1.512*10 J-12

InstituteInstituteof Physics, of Physics, Minsk, Minsk, BelarusBelarus

First blue InGaN/GaN

MQW optically pumped lasers

AIXTRON

G. P. Yablonskii, at all. Appl. Phys. Lett. v.29, No 13 (2001), p. 1953.

2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3

СиниеФиолетовые

T=300 KN2-лазер

GaNInGaN/GaN:SQWInGaN/GaN:MQW

Интенси

вность

[отн

. ед.

]

Энергия [эВ]

460 440 420 400 380Длина волны [нм]

12

GaN heterostructures grown on Si substratesGaN heterostructures grown on Si substrates

GaN/Si

Perfect qualityof GaN/Si laser cavity mirrors

GaN/Al2O3

MQW

SiAlN AlGaN

AlN AlGaNGaN

GaN

SiAlN AlGaN

MQW

GaN/AlN DBRGaN/AlN DBR

Trieste synchrotron

3.0 3.1 3.2 3.3 3.4 3.5

410 400 390 380 370 360

100 1000

GaN/AlGaN/AlN/Si

GaN/DBR/Si

Inte

nsity

[a.u

.]

Iexc [kW/cm2]

1

10

100

1000

Ithr = 700 kW/cm2

Ithr = 270 kW/cm2 N2 laser

Iexc [kW/cm2]

410 371 336 305 277 253 231 211

T = 300 K

Inte

nsity

[a. u

.]

Energy [eV]

Wavelength [nm]

DBR

SiAlN AlGaN

MQW

InGaN/GaN/DBR/SiIthr = 270 kW/cm2

InGaN/GaN/AlGaN/SiIthr = 700 kW/cm2

3,22 3,24 3,26 3,28 3,30 3,32 3,34 3,36 3,38 3,40

0

2000

384 382 380 378 376 374 372 370 368 366

GaN/DBR/Si GaN/AlGaN/AlN/Si

2

1

Iexc = 6 MW/cm2

T = 300 K

Gai

n [c

m-1]

Energy [eV]

Wavelength [nm]

GGaN/DBR/Si = 2200 cm-1GGaN/AlGaN/Si = 300 cm-1

Gain spectra

GaN/Si GaN/Si лазерылазеры

InstituteInstituteof Physics, of Physics, Minsk, Minsk, BelarusBelarus

For optoelectronics integration with Si electronocs

First InGaN/GaN MQW lasers on Si substrates

AIXTRON

•E. V. Lutsenko at all. Phys. Stat. Sol. (c) (2002). Vol. 0, No. 1, P. 272• A. L. Gurskii, at all. Phys. Stat. Sol. (c) (2002) Vol. 0, No. 1, P. 425• High temperature operation of optically pumped InGaN/GaN MQW heterostructure lasers grown on Si substrates.” (2003) http://ieeexplore.ieee.org/xpl/tocresult.jsp?isNumber=29749&page=3

•http://optics.org/articles/news/8/7/24/1•http://compoundsemiconductor.net/articles/news/6/7/28/1•LaserFocusWord Vol. 38, No.9, p.11

2.6 2.7 2.8 2.9

Iexc [kW/cm2]

370 335 305 253 210 177 149

T=300 K

Em

issi

on In

tens

ity [a

.u.]

Energy [eV]

470 460 450 440 430

Ppulse = 8 W

Laser threshold270-350 kW/cm2

1 0 2 1 0 3

1 0 1

1 0 2

Ith r= 3 3 0 k W /c m2

Em

iss

ion

in

ten

sit

y [

a.u

.]

Ie x c [k W /c m2]

InGaN/GaN MQW on Si

Wavelength [nm]

50 100 150 200 250 300 350

455

460

465

470

475

480

Генерациядо 360 0С

Температура [oC]

Длин

а во

лны

[нм

]

-0.030000.0021880.034380.066560.098750.13090.16310.19530.22750.25970.29190.32410.35620.38840.42060.45280.48500.51720.54940.58160.61380.64590.67810.71030.74250.77470.80690.83910.87130.90340.93560.96781.000

Laser threshold was reduced to 30 kW/cm2.Output power of MQW laser was increased from 8 W to 20 W.

Top = 3600CT0~200 K

InGaN/GaN/Si MQW InGaN/GaN/Si MQW laserslasers

0 100 200 300 400102

103

Experimental Formula aprox.

2)()(

)( 21

spsp

sp

thr hh

TI νη

ν⋅

Δ∝

T0=55

T0=190

Lase

r thr

esho

ld [k

W/c

m2 ]

Temperature [Co]High order transverse mode regime

2.81

2.8

2.79

2.78

2.77

-40 -20 0 20 40 60440

442

444

446

448

Angle[degrees]

Wav

elen

gth

[nm

]

Ener

gy [e

V]

Low threshold “blue” laser

Ithr = 25 kW/cm2

MQW

P = 35 W= 5%

Laser action of the InGaN/GaN/Si MQWs

SiAlN LT AlGaN

AlN LT

MQW

GaN

GaN

400 420 440 460 480

3 2.9 2.8 2.7 2.6

T = 300K

Energy [eV]

Wavelength [nm]

440 460 480 500 520 5400

100

200

300

400

500

600

700

800

900

1000

Possibility for green laser

Lase

r thr

esho

ld [k

W/c

m2 ]

Wavelength [nm]

Laser threshold increase with wavelength rise

Possibility for green lasing

Laser threshold of InGaN/GaN MQW/Si after substrate removal

400 420 440 460 480 500 520

3.1 3 2.9 2.8 2.7 2.6 2.5 2.4

200 250 300 350 400 4500

5000

10000

15000

20000

Iexc [kW/cm2]

Ithr=350 kW/cm2

Iexc , kW/cm2

410,2 370,9 336,1 305,1 277,4 252,7 230,5 210,6

Energy [eV]

Inte

nsity

[a.u

.]

λ = 474 nm

Wavelength [nm]

440 450 460 470

2.8 2.7

140 160 180 200 220 240 260 2800.0

5.0x103

1.0x104

1.5x104

2.0x104

Iexc [kW/cm2]

Ithr=200 kW/cm2

Iexc , kW/cm2

277,4 252,7 230,5 210,6 192,7 176,6 162,1 148,9

Energy [eV]

Inte

nsity

[a.u

.]

λ = 463 nmIthr = 200 kW/cm

2

Wavelength [nm]

Laser threshold - 350 kW/cm2 λ=474 nmNo lasing before liftoff

Laser threshold - 200 kW/cm2 λ=463 nmThreshold before liftoff: 300 kW/cm2

InGaN/GaN/AlInGaN/GaN/Al22OO33 and InGaN/GaN/Si LEDsand InGaN/GaN/Si LEDs

AlAl22OO33 substrate substrate Si substrateSi substrate

PPoptopt -- 0.3 0.3 мВтмВт

Width of strip Width of strip 1010--50 50 мкммкм

2.4 2.5 2.6 2.7 2.8 2.9

520 500 480 460 440 420

65 mA 60 mA 50 mA 45 mA 40 mA

Длина волны [нм]

Интенсивн

ость

[отн

.ед.

]

Энергия фотона [эВ]

AIXTRON

2.0 2.2 2.4 2.6 2.8 3.0 3.2

600 550 500 450 400

InGaN/GaNна Al2O3

интенсив

ность

[отн

.ед.

]

Энергия фотона [эВ]

Длина волны [нм]

18

ZnMgSSe/ZnSSe/ZnSe/CdSe QD heterostructuresZnMgSSe/ZnSSe/ZnSe/CdSe QD heterostructures

MgZnSSe

GaAs substrate

ZnSe/ZnSSe buffer

MgZnSSe

ZnSe

ZnSSe/ZnSe SL waveguide

Excita

tion las

er strip

e

200nm

[001]

TEM

10 nmTEM

[110]

Symmetrical waveguide with CdSe QDs grown by MBE

Asymmetrical waveguide with CdSe QD grown by MEE

ZnM

gSSe

1.0

m μ

ZnSS

e/Zn

Se

SL

68 n

m

ZnSe QW5nm

CdS

e Q

DS

ZnSS

e/Zn

Se

SL

166

nm

GaA

s s

ubst

rate

ZnS

Se/Z

nSe

SL 0.1

m μ

ZnSe QW5nm

ZnM

gSS

e0.

7mμ

ZnM

gSS

e0.

1mμ

CdS

e Q

DS

CdS

e Q

DS

ZnS

Se/Z

nSe

SL

ZnS

Se/Z

nSe

SL

CdS

e Q

DS

ZnSe QW5nm

ZnSe QW5nm

GaA

s s

ubst

rate

ZnM

gSS

e0.

7mμ

ZnM

gSS

e0.

1mμ

ZnS

Se/

ZnS

e S

L 0.1

m μ

ZnSe QW5nm

CdS

e Q

DS

GaA

s s

ubst

rate

QW

A

BC

QDs2.43 eV

2,3 2,4 2,5 2,6

0,0

0,2

0,4

0,6

0,8

1,0

550 540 530 520 510 500 490 480 470

CL at points A, B, C

CL

inte

nsity

(ar

b. u

nits

)

Energy [eV]

Wavelength [nm]

2,3 2,4 2,5 2,60,0

0,2

0,4

0,6

0,8

1,0

550 540 530 520 510 500 490 480 470 Wavelength [nm]

"dark" spot"bright" spots

CL

inte

nsity

(ar

b. u

nits

)

Energy [eV]

CathodoluminesceneCathodoluminescene of ZnMgSSe/of ZnMgSSe/ZnSSeZnSSe/ZnSe/CdSe/ZnSe/CdSe

CdZnSe SQW MBE

CdZnSe SQDS MEE

e-be

am

Sample

25 nm

Monochromator withphotomultiplier

Lock-in amplifierFibreoptics

CdSe/ZnSe/CdSe/ZnSe/ZnSSeZnSSe/ZnMgSSe /ZnMgSSe quantum dot sheet (QDS) heterostructuresquantum dot sheet (QDS) heterostructures

2,30 2,35 2,40 2,45 2,50 2,550

100

200

300

400

500530 520 510 500 490

MEE CdZnSe QDs

Energy [eV]

Abso

rptio

n [c

m-1]

Wavelength [nm]

2,2 2,3 2,4 2,5 2,6

560 540 520 500 480

MEE SQDS MBE SQDS

HeCd laserIexc.= 1.6 W/cm

2

T = 290 K

PL in

tens

ity [a

.u.]

Energy [eV]

Wavelength [nm]

MBE and MEE CdSe QD photoluminescence and absorption

MEE QDS lasers: heterostructure design and performanceInstituteInstituteof Physics, of Physics, Minsk, Minsk, BelarusBelarus

Structure C

Maximal laser external quantum efficiency 42 %Maximal laser differential quantum efficiency 55 %

32 %41 %

Structure C, 2 sheets Structure B, 1 sheet

520 525 530 535 540 545 550

100

1000

10000

100000

2,38 2,36 2,34 2,32 2,3 2,28 2,26

1,5 2,0 2,5 3,0 3,5 4,0

1000

10000

100000

Ith=2,5 kW/cm2

Lcav= 528.3 μmInte

nsity

, [a.

u.]

Iexc, [kW/cm2]

Lcav= 528 μm T=300 K

Iexc [kW/cm2]

3.67 3.36 3.08 2.82 2.51 2.24 2.05 1.88 1.73 1.58

Wavelength, [nm]

Inte

nsity

, [a.

u.]

Energy, [eV]

1 10 1000

5

10

15

20

25

30

35

40

45

structure B

structure C

T = 300 K

Lcav.= 483 μm

Lcav= 528 μm

Exte

rnal

qua

ntum

effi

cien

cy, [

%]

Iexc, [kW/cm2] 0 200 400 600

0

20

40

60

80

100

120

BC

T=300 K

Lcav.=483 μm

ηdiff=0,21404ηQdiff=0,412

N2-laser excitation

Lcav=528.3 μm

ηdiff=0,27 ηQdiff=0,55

Lase

r pul

se e

nerg

y, [n

J]Iexc, [nJ]

-40 -30 -20 -10 0 10 20 30 40

514

515

516

517

T = 290 K

Divergence ~ 300

Intensity [a.u.]

Angle [degree]

Wav

elen

gth

[nm

]

0490098001,47E41,96E42,45E42,94E43,43E43,92E44,41E44,9E45,39E45,88E46,37E46,86E47,35E47,84E48,33E48,82E49,31E49,8E41,029E51,078E51,127E51,176E51,225E51,274E51,323E51,372E51,421E51,47E51,519E51,568E51,617E51,666E51,715E51,764E51,813E51,862E51,911E51,96E52,009E52,058E52,107E52,156E52,205E52,254E52,303E52,352E52,401E52,45E5

Fundamental mode lasing

Excitation

Registration

Blue-green laser converter & InGaN/GaN/Si blue laserInstituteInstituteof Physics, of Physics, Minsk, Minsk, BelarusBelarus

Far-field pattern

Output characteristics of blue (~450 nm) InGaN/GaN laser grown on Si-substrate: q.e. = 5%, E=140 nJ, P=30 W. “Green” CdSe QD laser: P= 3 W

2,81

2,8

2,79

2,78

2,77

-40 -20 0 20 40 60440

442

444

446

448 RT

Intensity [a.u.]

Iexc = 3.4 IthrIthr=230 kW/cm

2

Lz=125 μm

Angle[degrees]

Wav

elen

gth

[nm

]

092,00184,0276,0368,0460,0552,0644,0736,0828,0920,01012110411961288138014721564165617481840193220242116220823002392248425762668276028522944303631283220331234043496358836803772386439564048414042324324441645084600

Ener

gy [e

V]

560 540 520 460 440

2,2 2,3 2,4 2,6 2,7 2,8 2,910

100

1000

10000

100000

1000000T=300 KCdSe QD

laser InGaN/GaN/SiMQW laser

Inte

nsity

, [a.

u.]

Energy, [eV]

Wavelength, [nm]

Thanks for yourattention !