自发有序Ga0.5In0.5P合金的静压光致发光研究

在０—７ＧＰａ静压范围内测量了自发有序Ga_0.5In_0.5P合金的室温光致发光谱．三块样品的常压带隙能量分别比无序样品低１１５，９２和４３ｍｅＶ，它们的压力系数也从无序样品的９２ｍｅＶ／ＧＰａ分别减小到７５，８１和８３ｍｅＶ／ＧＰａ．用Γ-Ｌ相互作用模型可以同时解释有序合金的带隙能量的降低以及压力系数的减小．得到的Γ-Ｌ相互作用势分别为０.１９，０.１５和０.１０ｅＶ．表明在自发有序Ga_0.5In_0.5P合金中存在着的

PHOTOLUMINESCENCE OF SPONTANEOUSLY ORDERED Ga0.5In0.5P ALLOY UNDER HYDROSTATIC PRESSURE

The photoluminescence of spontaneously ordered Ga_0.5In_0.5P alloy has been measured at room temperature and under hydrostatic pressure up to 7GPa. The direct-band gap of three ordered samples is lower than that of disordered sample by 115,92 and 43 meV at normal pressure, respectively. Their pressure coefficients are also reduced from 92meV/GPa of the disordered sample to 75,81 and 83meV/GPa for three ordered samples. Both the narrowing of the band gap and the reducing of its pressure coefficients can be well explained using a Γ-Ｌ interaction model. The obtained Γ-Ｌ interaction poteraction potential is 0.19,0.15 and 0.10 eV for three ordered samples, respectively. It confirms that the [111] order in the spontaneously ordered Ga_0.5In_0.5P alloy is the main reason for the band-gap narrowing. An obvious Γ-X anticrossing has been observed in sample C,but the Γ-X interaction potential(0.011eV)is one order of magnitude less than the Γ-L interaction. It indicates that a weak [001] order coexists with the main [111] order in sample C.