Optical effects of interdiffusion in GaAs/AlAs heterostructures: Atomic scale calculations
Optical effects of interdiffusion in GaAs/AlAs heterostructures: Atomic scale calculations
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GaAs/AlAs 异质结构中相互扩散的光学效应：原子尺度计算
DOI：
10.1063/1.117658
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发表时间：
1996
影响因子：
4
通讯作者：
H. Chacham
中科院分区：
文献类型：
--
作者：
B. Koiller;A. S. Martins;H. Chacham
我们通过紧结合模型计算研究了原子间扩散对AlAs/GaAs量子阱光学性质的影响。超级细胞的集合，每个细胞包含多达~ 104个原子，具有周期性边界条件，用于模拟异质结构。吸收阈值处光跃迁的振荡强度f是量子阱宽度W和扩散长度L的函数，随着L的增加，f经历一个不连续的跃迁到零，表明L大于扩散长度的临界值时的间接间隙行为。得到了f作为L/W1.7函数的统一行为。这允许通过简单的拟合公式将光学性质与结构性质联系起来。
We investigate the effects of atomic interdiffusion in the optical properties of AlAs/GaAs quantum wells through tight‐binding model calculations. Ensembles of supercells, each cell containing up to ∼104 atoms with periodic boundary conditions, are used to simulate the heterostructures. The oscillator strength f of optical transitions at the absorption threshold is calculated as a function of the quantum‐wells width W and the diffusion length L. As L increases, f undergoes a discontinuous transition to zero, indicating indirect‐gap behavior for L larger than a critical value of the diffusion length. A unified behavior of f as a function of L/W1.7 is found. This permits relating optical properties to structural properties through simple fitting formulas.