j.k. lee
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Effect of Mg doping in the barrier of InGaN/GaN multiple quantum well on optical power of light-emitting diodes. Sang-Heon Han, Chu-Young Cho, Sang-Jun Lee, Tae-Young Park, Tae-Hun Kim, Seung Hyun Park, Sang Won Kang, Je Won Kim, Yong Chun Kim, and Seong-Ju Park - PowerPoint PPT PresentationTRANSCRIPT
Effect of Mg doping in the barrier of Effect of Mg doping in the barrier of InGaN/GaN multiple quantum well on optical InGaN/GaN multiple quantum well on optical power of light-emitting diodespower of light-emitting diodes
Sang-Heon Han, Chu-Young Cho, Sang-Jun Lee, Tae-Young Park, Tae-Hun Kim, Seung Hyun Park, Sang Won Kang, Je Won Kim, Yong Chun Kim, and Seong-Ju Park
APPLIED PHYSICS LETTERS 96, 051113 , 2010
J.K. Lee
OutlineOutline
Introduction
Experiment
Results and discussion
Conclusion
IntroductionIntroduction
Mg doping in the barriers of MQW enhances photoluminescence intensity, thermal stability, and internal quantum efficiency of LED.
The improvement in output power is attributed to the enhanced hole injection to well layers in MQW with Mg-doped barriers.
Chip Size ： 300*300 μm2
Sapphire
buffer
N-GaN 2μm
MQW 5 period
N
Ti/Au
P-GaN 200 nm
P-AlGaN 20 nm
ITO
P
Ti/Al
ExperimentExperiment
3nm InGaN Well 750℃
8nm GaN Barrier 800℃
A
u-GaN / Mg-doped GaN / u-GaN
B
2 nm / 4 nm / 2 nm
Mg-doped GaN concentration 4.94*1016/cm3
u-GaN concentration 5.02*1018/cm3
ExperimentExperiment
Mg doped GaN
N-GaN P-AlGaN
Un doped GaN Un doped GaN
Results and discussionResults and discussion
FIG. 1. (Color online) (a) Room temperature PL spectra of LED A and LED B (inset: high resolution x-ray diffraction -2 scans for the GaN 0002 reflection of LED A and LED B).
Results and discussionResults and discussion
FIG. 1. (b) PL spectra of LED A before and after RTA, (c) PL spectra of LED B before and after RTA.
15%25%
63%
Results and discussionResults and discussion
FIG. 2. Color online Integrated PL intensities as a function of 1/T for LED A and LED B.
Results and discussionResults and discussion
FIG. 3. Color online AFM images of surface morphologies of a LED A and b LED B.
3.8*108/cm2 2.96*108/cm2
9.62 Å 6.98 Å22%22%
Results and discussionResults and discussion
FIG. 4. Color online a I-V curve of LED A and LED B, b light output power of LED A and LED B as a function of current.
3.54V3.63V
Results and discussionResults and discussion
FIG. 5. Color online Energy band diagrams of well and barrier layer of LED A and LED B at 4 V, a valence band and b conduction band. Carrier concentration throughout MQW at 4 V, c LED A and d LED B.
ConclusionConclusion
We investigated the effect of Mg doping in the barrier layers of MQW of InGaN/GaN LED.
PL measurements showed that thermal stability was improved and IQE was increased for LED with Mg-doped MQW barriers.
The reduced defect density and RMS roughness of MQWs were also confirmed by AFM images.
Influence of Mg Doping on the Morphological, Influence of Mg Doping on the Morphological, Optical, and Structural Properties of Optical, and Structural Properties of InGaN/GaN Multiple Quantum WellsInGaN/GaN Multiple Quantum Wells
Z. CHEN, N. FICHTENBAUM, D. BROWN, S. KELLER, U.K. MISHRA, S.P. DENBAARS, and S. NAKAMURA
Journal of ELECTRONIC MATERIALS, Vol. 37, No. 5, 2008
OutlineOutline
Introduction
Experiment
Results and discussion
Conclusion
References
IntroductionIntroduction
The V-defect density was observed to decrease with increasing magnesium doping concentration from 109 cm-2 (no doping) to 106 cm-2 (Cp2Mg: 0.04 sccm) and further to 0 (Cp2 Mg: 0.2 sccm).
These results suggest that magnesium doping in MQWs might improve the optical properties of GaN photonic devices.
Chip Size ： 300*300 μm2
Sapphire
Buffer 25nm
N-GaN 2μm
MQW 5 period
N
Ti/Au
P-GaN 200 nm
P-AlGaN 20 nm
ITO
P
Ti/Al
ExperimentExperiment
Barrier 3 nm
Well 10 nm
Cp2Mg doping precursor flow was from 0 sccm to 0.04 sccm and 0.2sccm.
Results and discussionResults and discussion
Fig. 1. 5 lm * 5 lm AFM images of InGaN/GaN MQW at different Mg doping levels: (a) 0 sccm, (b) 0.04 sccm, and (c) 0.2 sccm. The height scale is 10 nm for all samples.
0 sccm 0.04 sccm
0.2 sccm
1*109/cm-2 4*106/cm-2
Results and discussionResults and discussion
Fig. 2. 1 lm * 1 lm AFM images of InGaN/GaN MQW at different Mg doping levels: (a) 0 sccm, (b) 0.04 sccm, and (c) 0.2 sccm. The height scale is 10 nm for all samples.
0 sccm 0.04 sccm
0.2 sccm
Results and discussionResults and discussion
Fig. 3. PL spectra of InGaN/GaN MQW at different Mg doping levels.
ConclusionConclusion
The AFM measurements indicated that Mg doping improved the surface morphology of the MQWs and enhanced twodimensional growth.
The density of the V-defects was observed to decrease from 109 cm-2 (undoped) to 106 cm-2 and further to zero with increasing Mg doping concentration.
ReferencesReferences
1. Sang-Heon Han, Chu-Young Cho, Sang-Jun Lee, Tae-Young Park, Tae-Hun Kim, Seung Hyun Park, Sang Won Kang, Je Won Kim, Yong Chun Kim, and Seong-Ju Park ,” Effect of Mg doping in the barrier of InGaN/GaN multiple quantum well on optical power of light-emitting diodes ” , APPLIED PHYSICS LETTERS 96, 051113 , 2010.
2. Z. Chen, N. Fichtenbaum, D. Brown, S. Keller, U.K. Mishra, S.P. Denbaars, and S. Nakamura ,” Influence of Mg Doping on the Morphological, Optical, and Structural Properties of InGaN/GaN Multiple Quantum Wells ” , Journal of ELECTRONIC MATERIALS, Vol. 37, No. 5, 2008.