Effects of in doping on the optical and electrical properties of ZnTe crystal grown by MVB-Te solvent method

The electrical and optical properties of In:ZnTe and ZnTe crystals grown by MVB-Te solvent method were characterized. Observation and statistical analysis of Te inclusions in In:ZnTe and ZnTe crystals show that In dopant has no significant effect on the distribution and the size of Te inclusions by IRTM (IR transmission microscopy). Besides, IR transmission spectra of In:ZnTe and ZnTe crystals show flat curves and demonstrate that average transmittances are approximately 60%, which suggests In dopant doesn't result in serious lattice and impurity absorption. However, I-V measurement shows that In dopant increases the resistivity of ZnTe crystal for 5 orders of magnitude. Hall test indicates that In:ZnTe and ZnTe crystals are both p-type. The carrier concentration of In:ZnTe crystal is decreased 4 orders of magnitude due to In dopant compensating on V_Zn in the crystal. Comparing UV-Vis-NIR transmission spectra of In:ZnTe and ZnTe crystals, it is suggested that the absorption edge drifts from 550 nm in ZnTe crystal to 560 nm in In:ZnTe crystal, which is possibly attributed to the shallow level defects associated with In dopant leading to the absorption band tail phenomenon.