The influence of strain-reducing layer on strain distribution and ground state energy levels of GaN/AlN quantum dot  

作　　者：刘玉敏 俞重远 任晓敏 徐子欢 

机构地区：[1]Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications),Ministry of Education

出　　处：《Chinese Physics B》2009年第10期4136-4142,共7页中国物理B（英文版）

基　　金：Project supported by the National High Technology Research and Development Program of China (Grant No 2009AA03Z405);the National Natural Science Foundation of China (Grant No 60644004);the High School Innovation and Introducing Talent Project (Grant No B07005)

摘　　要：This article deals with the strain distributions around GaN/AlN quantum dots by using the finite element method. Special attention is paid to the influence of Al0.2Ga0.8N strain-reducing layer on strain distribution and electronic structure. The numerical results show that the horizontal and the vertical strain components are reinforced in the GaN quantum dot due to the presence of the strain-reducing layer, but the hydrostatic strain in the quantum dot is not influenced. According to the deformation potential theory, we study the band edge modifications and the piezoelectric effects. The result demonstrates that with the increase of the strain reducing layer, the transition energy between the ground state electron and the heavy hole increases. This result is consistent with the emission wavelength blue shift phenomenon observed in the experiment and confirms that the wavelength shifts toward the short wavelength range is realizable by adjusting the structure-dependent parameters of GaN/AlN quantum dot.This article deals with the strain distributions around GaN/AlN quantum dots by using the finite element method. Special attention is paid to the influence of Al0.2Ga0.8N strain-reducing layer on strain distribution and electronic structure. The numerical results show that the horizontal and the vertical strain components are reinforced in the GaN quantum dot due to the presence of the strain-reducing layer, but the hydrostatic strain in the quantum dot is not influenced. According to the deformation potential theory, we study the band edge modifications and the piezoelectric effects. The result demonstrates that with the increase of the strain reducing layer, the transition energy between the ground state electron and the heavy hole increases. This result is consistent with the emission wavelength blue shift phenomenon observed in the experiment and confirms that the wavelength shifts toward the short wavelength range is realizable by adjusting the structure-dependent parameters of GaN/AlN quantum dot.

关 键 词：quantum dot strain distribution electronic structure 

分 类 号：O471.1[理学—半导体物理]