scholarly journals Role of Strain-Induced Microscale Compositional Pulling on Optical Properties of High Al Content AlGaN Quantum Wells for Deep-Ultraviolet LED

2022 ◽  
Vol 17 (1) ◽  
Author(s):  
Shiqiang Lu ◽  
Zongyan Luo ◽  
Jinchai Li ◽  
Wei Lin ◽  
Hangyang Chen ◽  
...  

AbstractA systematic study was carried out for strain-induced microscale compositional pulling effect on the structural and optical properties of high Al content AlGaN multiple quantum wells (MQWs). Investigations reveal that a large tensile strain is introduced during the epitaxial growth of AlGaN MQWs, due to the grain boundary formation, coalescence and growth. The presence of this tensile strain results in the microscale inhomogeneous compositional pulling and Ga segregation, which is further confirmed by the lower formation enthalpy of Ga atom than Al atom on AlGaN slab using first principle simulations. The strain-induced microscale compositional pulling leads to an asymmetrical feature of emission spectra and local variation in emission energy of AlGaN MQWs. Because of a stronger three-dimensional carrier localization, the area of Ga segregation shows a higher emission efficiency compared with the intrinsic area of MQWs, which is benefit for fabricating efficient AlGaN-based deep-ultraviolet light-emitting diode.

2016 ◽  
Vol 10 (1) ◽  
pp. 011004 ◽  
Author(s):  
Sakib Muhtadi ◽  
Seong Mo Hwang ◽  
Antwon L. Coleman ◽  
Alexander Lunev ◽  
Fatima Asif ◽  
...  

2010 ◽  
Vol 49 (4) ◽  
pp. 040206 ◽  
Author(s):  
Krishnan Balakrishnan ◽  
Vinod Adivarahan ◽  
Qhalid Fareed ◽  
Mohamed Lachab ◽  
Bin Zhang ◽  
...  

2000 ◽  
Vol 5 (S1) ◽  
pp. 696-702 ◽  
Author(s):  
Hideki Hirayama ◽  
Yasushi Enomoto ◽  
Atsuhiro Kinoshita ◽  
Akira Hirata ◽  
Yoshinobu Aoyagi

We demonstrate 230-250 nm efficient ultraviolet (UV) photoluminescence (PL) from AlN(AlGaN)/AlGaN multi-quantum-wells (MQWs) fabricated by metal-organic vapor-phase-epitaxy (MOVPE). Firstly, we show the PL properties of high Al content AlGaN bulk (Al content: 85-95%) emitting from near band-edge. We systematically investigated the PL properties of AlGaN-MQWs consisting of wide bandgap AlGaN (Al content: 53-100%) barrier. We obtained efficient PL emission of 234 and 245 nm from AlN/Al0.18Ga0.82N and Al0.8Ga0.2N/Al0.18Ga0.82N MQWs, respectively, at 77 K. The optimum value of well thickness was approximately 1.5 nm. The emission from the AlGaN MQWs were several tens of times stronger than that of bulk AlGaN. We found that the most efficient PL is obtained at around 240 nm from AlGaN MQWs with Al0.8Ga0.2N barriers. Also, we found that the PL from AlGaN MQW is as efficient as that of InGaN QWs at 77 K.


1999 ◽  
Vol 595 ◽  
Author(s):  
Hideki Hirayama ◽  
Yasushi Enomoto ◽  
Atsuhiro Kinoshita ◽  
Akira Hirata ◽  
Yoshinobu Aoyagi

AbstractWe demonstrate 230-250 nm efficient ultraviolet (UV) photoluminescence (PL) from AlN(AlGaN)/AlGaN multi-quantum-wells (MQWs) fabricated by metalorganic vapor-phase-epitaxy (MOVPE). Firstly, we show the PL properties of high Al content AlGaN bulk (Al content: 85-95%) emitting from near band-edge. We systematically investigated the PL properties of AlGaN-MQWs consisting of wide bandgap AlGaN (Al content: 53-100%) barrier. We obtained efficient PL emission of 234 and 245 nm from AlN/Al0.18Ga0.82N and Al0.8Ga0.2N/Al0.18Ga0.82N MQWs, respectively, at 77 K. The optimum value of well thickness was approximately 1.5 nm. The emission from the AlGaN MQWs were several tens of times stronger than that of bulk AlGaN. We found that the most efficient PL is obtained at around 240 nm from AlGaN MQWs with Al0.8Ga0.2N barriers. Also, we found that the PL from AlGaN MQW is as efficient as that of InGaN QWs at 77 K.


2016 ◽  
Vol 37 (5) ◽  
pp. 513-518
Author(s):  
李金钗 LI Jin-chai ◽  
季桂林 JI Gui-lin ◽  
杨伟煌 YANG Wei-huang ◽  
金 鹏 JIN Peng ◽  
陈航洋 CHEN Hang-yang ◽  
...  

Nanoscale ◽  
2021 ◽  
Author(s):  
Shiqiang Lu ◽  
Xinjun Jiang ◽  
Yaozeng Wang ◽  
Kai Huang ◽  
Na Gao ◽  
...  

The external quantum efficiency of a high-Al content (>0.6) AlGaN deep-ultraviolet (DUV) light-emitting diode is typically below 1% in the sub-250 nm wavelength range. One of the main reasons for...


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Wang ◽  
Feng Liang ◽  
Degang Zhao ◽  
Zongshun Liu ◽  
Jianjun Zhu ◽  
...  

Abstract Three InGaN/GaN MQWs samples with varying GaN cap layer thickness were grown by metalorganic chemical vapor deposition (MOCVD) to investigate the optical properties. We found that a thicker cap layer is more effective in preventing the evaporation of the In composition in the InGaN quantum well layer. Furthermore, the quantum-confined Stark effect (QCSE) is enhanced with increasing the thickness of GaN cap layer. In addition, compared with the electroluminescence measurement results, we focus on the difference of localization states and defects in three samples induced by various cap thickness to explain the anomalies in room temperature photoluminescence measurements. We found that too thin GaN cap layer will exacerbates the inhomogeneity of localization states in InGaN QW layer, and too thick GaN cap layer will generate more defects in GaN cap layer.


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