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Strain distributions and electronic structure of three-dimensional InAs/GaAs quantum rings 下载免费PDF全文
This paper presents a finite element calculation for the
electronic structure and strain distribution of self-organized
InAs/GaAs quantum rings. The strain distribution calculations are
based on the continuum elastic theory. An ideal three-dimensional
circular quantum ring model is adopted in this work. The electron
and heavy-hole energy levels of the InAs/GaAs quantum rings are
calculated by solving the three-dimensional effective mass
Schr?dinger equation including the deformation potential and
piezoelectric potential up to the second order induced by the
strain. The calculated results show the importance of strain and
piezoelectric effects, and these effects should be taken into
consideration in analysis of the optoelectronic characteristics of
strain quantum rings. 相似文献
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量子点的光学特性与量子点的大小均匀性、密度、内部应变以及隔离层的厚度等有密切关系.文中从理论角度定量研究了GaNXAs1-X应变补偿层对InAs/GaAs量子点生长质量的改善作用,分析了应变补偿层对隔离层厚度减小的作用.讨论了应变补偿层的补偿位置和补偿层N组分X对量子点生长时局部应变和体系应变的补偿作用.分析了应变补偿层对体系应变的减少作用,并计算了相邻层量子点的垂直对准概率.研究结果对实验中应变补偿的优化和高质量量子点阵列的生长实现提供了理论依据. 相似文献
3.
Self-organized GaN/AlN hexagonal quantum-dots:strain distribution and electronic structure 下载免费PDF全文
This paper presents a finite element method of calculating strain distributions in and around the self-organized GaN/AlN hexagonal quantum dots. The model is based on the continuum elastic theory, which is capable of treating a quantum dot with an arbitrary shape. A truncated hexagonal pyramid shaped quantum dot is adopted in this paper. The electronic energy levels of the GaN/AlN system are calculated by solving a three-dimension effective mass Shrodinger equation including a strain modified confinement potential and polarization effects. The calculations support the previous results published in the literature. 相似文献
4.
The influence of strain-reducing layer on strain distribution and ground state energy levels of GaN/AlN quantum dot 下载免费PDF全文
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. 相似文献
5.
We present equilibrium composition maps in InGaAs/GaAs conic strained quantum dots, using the finite element method and quadratic programming optimization method. The axis-symmetric model is adopted. We compare the steep islands with the shallow islands and determine the influence of entropie energy. The difference of equilibrium composition maps between the single dot and the quantum dot stacks is also discussed. 相似文献
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