HgCdTe组分异质结的生长与表征

Growth and Characterization of HgCdTe Compositional Heterojunctions

采用富碲水平推舟液相外延生长方式,在(111)晶向的碲锌镉衬底上生长了双层组分异质HgCdTe外延薄膜,并对生长后的薄膜质量进行了评价.使用染色法和红外透射光谱数值拟合的方法,对两层薄膜的厚度进行了表征,并建立了一个双层薄膜纵向组分分布模型;对材料的电学参数进行测量的结果显示,双层异质液相外延样品中长波层的载流子迁移率较之单层液相外延样品略高,原因可能是中波覆盖层对长波外延层起到了钝化作用.

The HgCdTe epilayers reported here were double-layers compositional heterojunctions grown by Te-rich liquid phase epitaxy in a horizontal slider system. The substrates adopted were （111） oriented CdZnTe with about 4% Zn. The epilayers were evaluated by the chemical staining method and infrared transmission spectra measurements. A phenomenological model was also established to characterize the profile of the Cd composition along the growth direction in the HgCdTe epilayer. The results of the electrical measurements showed that the carrier mobility of the long-wave layer beneath the double-layer sample was slightly higher than that of the single-layer sample grown with almost the same conditions. The reason for the increase of the mobility can be ascribed to the passive effect of the middle-wave cap layer.