Thermal treatment induced change of diluted oxygen doped ZnTe films grown by metal-organic chemical vapor deposition

Abstract

In this paper, the authors report the growth of diluted oxygen doped ZnTe films (ZnTe:O) by metal-organic chemical vapor deposition (MOCVD). The effect of a post thermal annealing on the properties of the highly mismatched films has been investigated. It is found that the in-situ doping leads to an effective incorporation of oxygen into ZnTe films with different occupation configurations, either on Zn or on Te site. The subsequent annealing process in a vacuum ambient leads to an enhancement of the oxygen incorporation into the ZnTe:O films due to the diffusion of the residual oxygen, while the annealing with the same as-grown sample covered on top of the surface (denoted as “face-to-face” annealing in the text) is beneficial to the improvement of the film quality with manifest intermediate band emission at around 1.9 eV as revealed by the low-temperature photoluminescence. This study indicates that the mass-productive MOCVD technique may be suitable for the growth of highly mismatched ZnTe:O films for the application of the intermediate band solar cell.