Passivation of double-positioning twin boundaries in CdTe

We present density-functional total-energy calculations to investigate the passivation effects of impurity elements such as Br, Cl, S, O, H, and Na on double-positioning twin boundaries in CdTe. We find that Br, Cl, S, and O atoms present passivation effects on the boundaries with different degrees, whereas H and Na do not passivate the boundaries. Of all these impurities, Cl atoms present the best passivation effects on the double-positioning twin boundaries. The superior passivation effects are realized by either terminating the Cd atoms with dangling bonds, or substituting the Te atoms with dangling bonds in the double-positioning twin boundaries in CdTe by Cl atoms.