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用光荧光和光吸收的实验方法研究了InGaAs/GaAs应变量子阱低温下的光谱展宽机理。实验观察到激子谱线半宽随着InGaAs层厚度和In的组分增加而增大。采用有效晶体近似的方法分析了实验数据,发现样品中合金组合无序引起的激子谱线展宽是主要的光谱展宽机理。实验中还发现与轻空穴有关的吸收光谱结构在升温过程中由吸收峰变为台阶状的谱结构。该现象可用与轻空穴有关的吸收为空间间接跃过来解释。
The mechanism of spectral broadening at low temperature of InGaAs / GaAs strained quantum wells was investigated by means of fluorescence and light absorption experiments. It has been observed experimentally that the half-width of the exciton line increases with the thickness of the InGaAs layer and the composition of In. The effective crystal approximation method is used to analyze the experimental data. It is found that the exciton broadening caused by the unordered alloy composition in the sample is the main spectral broadening mechanism. In the experiment, it was also found that the structure of the absorption spectrum associated with light holes changes from an absorption peak to a step-like spectral structure during heating. This phenomenon can be explained by the indirect absorption of light holes as an indirect jump in space.