摘要
用多层模型和膜系传递矩阵计算了HgCdTe/CdZnTe外延薄膜的红外透射光谱,结果表明组分扩散区主要影响透射光谱的干涉条纹和透射率小于10%的区域,而组分梯度区则影响吸收边斜率.横向组分波动也将影响透射光谱的吸收边斜率,当组分均方差小于0. 005时,横向组分波动对透射光谱影响可以忽略.用新的组分分布模型计算了HgCdTe/CdZnTe液相外延薄膜的理论透射光谱,并运用非线性二乘法使理论曲线能够很好地与实验结果吻合,从而获得了更加可信的HgCdTe外延薄膜的纵向组分分布和厚度参数.
Theoretical infrared transmission spectra of HgCd Te/CdZnTe epilayers are calculated by using multilayer model and transfer matrix.The results show that the interference peaks and the tail region of the transmission curves are mainly affected by compositional diffusion region and the cutoff slope depends on composition gradient.And it is found that transverse composition nonuniformity results in the decreasing of the cutoff slope of the transmission curves.If composition deviation in HgCdTe epilayers is less than 0.005,the influence of transverse composition nonuniformity on the transmission curves can be neglected.Then the theoretical infrared transmission spectra of LPE-HgCdTe/CdZnTe epilayers are calculated by using new composition profile.And the measured transmission spectra are fitted best by nonlinear least squares and the composition profile and thickness of HgCdTe epilayers is obtained.
基金
国家自然科学基金委创新研究群体科学基金资助项目(批准号:60221502)~~
关键词
多层模型
膜系传递矩阵
HgCdTe外延薄膜
纵向组分分布
横向组分波动
multilayer model
transfer matrix
HgCdTe epilayers
longitudinal composition profile
transverse composition nonuniformity
