Improvement in the ability to block Hg out diffusion from Hg_(1-x)Cd_xTe by hydrogenation

摘要

Hydrogenation and double-layer passivation of mercury cadmium telluride (Hg_(1-x)Cd_xTe or MCT) is studied and compared with passivation by a single CdTe layer. Two different passivated structures, namely CdTe/hydrogenated MCT and ZnS/CdTe/MCT, are investigated using Rutherford backscattering spectroscopy. No significant improvement in the compositional profile of CdTe/MCT is seen in a doubly passivated ZnS/CdTe/MCT structure, i.e. the presence of a ZnS passivating layer does not improve the compositional profile in CdTe/MCT structures. Similar to the CdTe/MCT sample, ZnS/CdTe/MCT was also found to have a 35 nm thick interlayer mixing region between CdTe and MCT. In CdTe/hydrogenated MCT the interface is found to be sharp and suggests complete blockage of Hg out diffusion by hydrogenation, and it is also observed that CdTe/hydrogenated MCT preserves its effectiveness in preventing the Hg out diffusion even after annealing at 80℃ in a vacuum. This improvement may be due to restriction of Hg vacancy diffusion by hydrogenation.