生长在Ge_xSi_（1－x）（001）衬底上应变GaAs层的光学性质

采用紧束缚方法计算了生长在ＧｅｘＳｉ１－ｘ（００１）衬底上的应变ＧａＡｓ层带间光跃迁的振子强度以及三次非线性光极化率，讨论了振子强度及三次非线性光极化率随衬底合金组分ｘ的变化关系。计算结果表明：对所有ｘ值，及随ｘ的变小而变小；及随ｘ的变小而变大。对ｎ型ＧａＡｓ／ＧｅｘＳｉ１－ｘ（００１），应变使和变小；对ｐ型ＧａＡｓ／ＧｅｘＳｉ１－ｘ（００１），应变使变大，但使变小。

Optical Properties of Strained GaAs Layers Grown on the Ge_xSi_(1-x)(001) Substrates

The oscillator strength for interband transitions and third order nonlinear optical susceptibilities of strained GaAs layers grown on the GexSi1-x(001) substrates are calculated in tight-binding frame. Thier dependences on the substrate alloy composition x are discussed. The calculating results show that fHc[001]=0 for all x. As x decreases, fHc[100],fLC[001] and fSC[100]decrease and fLC[100],fSC[001]increase. For n-GaAs/ GexSi1-x(001) the strain turns both Xxxxx and Xzzzz decreasing and for p-GaAs/ GexSi1-x(001) the strain turns Xxxxx growing and Xzzzz decreasing.