应变超晶格(InxGa1-xAs)n/(GaAs)n(001)的电子结构和光学性质

用半经验的紧束缚方法ｓｐ３ｓ＊计算了薄层应变超晶格（ＩｎｘＧａ１－ｘＡｓ）ｎ／（ＧａＡｓ）ｎ（００１）的电子结构．给出了组份Ｘ为０．５３的超晶格（ＩｎｘＧａ１－ｘＡｓ）ｎ／（ＧａＡｓ）ｎ的带隙值随层厚ｎ的变化关系，以及超晶格（ＩｎｘＧａ１－ｘＡｓ）１２／（ＧａＡｓ）１２的带隙值随组份Ｘ的变化关系．在得到超晶格能量本征值和本征函数的基础上，计算了该超晶格系统的光学介电函数虚部，并与体材料ＧａＡｓ和体合金ＩｎｘＧａ１－ｘＡｓ的光学性质作了比较．计算结果表明，应变超晶格在较宽的能量范围有较好的光谱响应．

The Electronic and Optical Properties of the Strained Superlattices (InxGa1-xAs)n/(GaAs)n(001)

The semi empirical tight binding model sp 3s * was used to calculate the band structure of the thin strained superlattices (In x Ga 1-x As) n /(GaAs) n (001). The band gap of strained (In 0.53 Ga 0.47 As) n /(GaAs) n as a function of layer number n is given out, and the dependence of the band gap of strained (In x Ga 1-x As) 12 /(GaAs) 12 on composition x is also presented.The imaginary parts of dielectric functions for the superlattices have been obtained on the basis of the relatively accurate calculated eignvalues and eignvectors of the superlattices, and then the optical properties of the superlattices were compared with that of the bulk GaAs and the alloy In x Ga 1-x As. It is shown that the strained superlattices (In x Ga 1-x As) n /(GaAs) n (001) have good optical response over a wide of energy range ,and the intensity of their main absorption peaks drops drastically with the increasing of superlattices layer numbers.