Deep levels in In-doped CdTe epitaxial films grown on p-CdTe substrates

Deep-level transient spectroscopy measurements have been carried out to investigate the behavior of the deep levels existing in In-doped n-CdTe grown by molecular beam epitaxy on nominally undoped p-CdTe (211) B-orientation substrates. One electron-trap of the as-grown In-doped CdTe epilayer was observed, and the trap originated from complexes of Cd vacancies and In impurities. After the In-doped CdTe epilayer was annealed, one new trap at Ec − 0.49 eV was observed, and the deep level was related to the Te vacancies or the Cd interstitials. These results indicate that the electron deep trap in In-doped CdTe epilayers is affected remarkably by annealing and that the variation of the position of the deep level due to thermal treatment is a significant problem for electronic devices.