Electronic Structures of a Quantum Well of Alloy Semiconductor

在相干势近似下，我们从理论上研究了由二元合金半导体A&lt；1-x&gt；Bx构成的量子阱(QW)的电学和光学性质。在由N_xxN_yxN_z格位组成的势垒中，单粒子(电子、空穴、Frenkel激子)采用紧束缚模型。对角随机性的影响被简化为相干势S(E)，假定对所有位置都是相同的，并由平均格林函数自洽地确定。对于板条(∞，∞，N_z)和线(∞，N_y，N_z)，态密度ρ(E)由N_z(或N_yxN_z)子带组成，每个子带都表现出两(一)维范-霍夫奇点。当x(或1-x)较小时，B(A)杂质带总是出现在最低(最高)主带的低(高)能侧。随着井宽变窄和/或降维，Δ/t的边界减小，区分了混合型和持续型。这一结果已发表在MRS 2000秋季学术讨论会G“GaN及相关合金”639(2001)和Phys上。统计一下。索尔(B)，229。

We have theoretically studied electyronic and optical properties of a quantum well (QW) in which the well region is constructed from a binary alloy semiconductor A_<1-x>B_x in the coherent potential approximation (CPA). A tight binding model is used for a single particle (electron, hole, Frenkel exciton) in the well composed by a rectangular array of N_xxN_yxN_z sites. The effect of the diagonal randomness is reduced to the coherent potential S(E), which is assumed to be the same for all sites, and is selfconsistently determined with the average Green's function. For a slab (∞, ∞, N_z) and wire (∞, N_y, N_z), the density of states ρ(E) is composed of N_z (or N_yxN_z) subbands, each shows the two (one)-dimensional van-Hove singularity. When x (or 1-x) is small, a B (A) impurity-band always appears at the lower (higher) energy side of the lowest (highest) host-band. As the well width becomes narrower and/or the dimensionality decreases, the boundary for Δ/t decreases which separates the amalgamation type and the persistence type. The results have been published in the Proceeding of MRS 2000 Fall symposium G "GaN and Related Alloys" 639 (2001) and Phys. Stat. Sol. (b), 229.