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采用椭圆偏振光谱技术研究了射频磁控溅射生长非晶态碲镉汞(amorphous Hg1-xCdxTe,amorphous MCT,a-MCT)薄膜的光学性质,发现非晶态碲镉汞薄膜的介电函数谱特征与晶态碲镉汞材料的明显不同,表现出与其他非晶态半导体材料类似的“波包”结构特征。基于修正的FB模型在1.0～4.0eV的能量范围内对实验结果进行了拟合分析,得到了不同组分非晶态碲镉汞薄膜的光学带隙随组分关系。通过与单晶碲镉汞光学带隙随组分变化关系的对比研究,结果表明碲镉汞的结构从晶态向非晶态转变过程中,材料的光学待续发生了明显的“蓝移”。
The optical properties of amorphous Hg1-xCdxTe amorphous MCT (a-MCT) films grown by radio-frequency magnetron sputtering were studied by ellipsometry. The dielectric constant spectra of amorphous HgCdTe thin films The characteristics are markedly different from the crystalline HgCdTe materials and show similar “wave package” structural features as other amorphous semiconductor materials. Based on the modified FB model, the experimental results were fitted and analyzed in the energy range of 1.0-4.0 eV, and the optical bandgap of the amorphous mercury cadmium telluride thin films with different compositions was obtained. Through the comparison with the optical band gap of monocrystal HgCdTe with the change of composition, the results show that there is a clear “blue shift” in the optical properties of the structure of HgCdTe from the crystalline state to the amorphous state ".