Comparison of zinc-blende and wurtzite GaN semiconductors with spontaneous polarization and piezoelectric field effects
Comparison of zinc-blende and wurtzite GaN semiconductors with spontaneous polarization and piezoelectric field effects
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DOI：
10.1063/1.371915
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发表时间：
2000-01-01
影响因子：
3.2
通讯作者：
Chuang, SL
中科院分区：
文献类型：
--
作者：
Park, SH;Chuang, SL
本文从理论上研究了（001）、（111）和（0001）取向纤锌矿晶体的电子性质，并考虑了自发极化和压电场效应。结果表明，（001）和（111）晶向的纤锌矿基锌单晶价带的Luttinger-Kohn 6 × 6哈密顿量和纤锌矿（0001）晶向的哈密顿量都可以块对角化为两个3 × 3哈密顿量，它们具有本征值和本征向量的解析解.然后，我们推导出的应变相关的带边有效质量和带间光学矩阵元素的锌锗和纤锌矿GaN晶体的解析表达式，并比较它们的数值结果以及价带结构。虽然在材料中的压缩应变的锌双量子威尔斯阱，如GaAs和ZnSe为基础的系统显示降低的阈值载流子密度由于较低的面内有效质量，我们发现，对于GaN的有效质量的减少与双轴压缩应变是不显着的锌双和纤锌矿结构。另一种方法是应用单轴应变来减少两种结构中的面内有效质量。研究还发现，对于（111）Zn结构，PZ场对GaN/AlGaN量子阱结构的价带结构以及电子和空穴波函数的重叠积分有显著影响;对于（0001）纤锌矿结构，PZ场和自发极化都对GaN/AlGaN量子阱结构的价带结构以及电子和空穴波函数的重叠积分有显著影响。(C)2000年美国物理学会。【S0021-8979（00）05101-X】。
The electronic properties of (001)-, (111)-oriented zinc-blende and (0001)-oriented wurtzite crystals are investigated theoretically, where the spontaneous polarization and piezoelectric (PZ) field effects are taken into account. We show that the Luttinger-Kohn 6x6 Hamiltonians for the valence bands of the zinc-blende crystals written in the wurtzite bases for (001) and (111) crystal orientations and the Hamiltonian for the (0001)-orientation of wurtzite crystals can all be block diagonalized to two 3x3 Hamiltonians, which have analytical solutions for eigenvalues and eigenvectors. We then derive analytical expressions for the strain dependent band-edge effective masses and interband optical matrix elements of zinc-blende and wurtzite GaN crystals and compare their numerical results as well as valence band structures. Although the compressively strained zinc-blende quantum wells in materials such as GaAs- and ZnSe-based systems show reduced threshold carrier densities due to the lower in-plane effective mass, we find that for GaN the reduction of the effective mass with the biaxial compressive strain is not significant in both zinc-blende and wurtzite structures. An alternative method is the application of a uniaxial strain to reduce the in-plane effective masses in both structures. It is also found that the valence band structures and the overlap integral of the electron and hole wave functions of GaN/AlGaN quantum-well structures are affected significantly by the PZ field for (111) zinc-blende structures and by both the spontaneous polarization and PZ fields for (0001) wurtzite structures. (C) 2000 American Institute of Physics. [S0021-8979(00)05101-X].