Atomic structure of acceptors in Cd0.22Hg0.78Te: Discrimination between vacancies and ions based on positron lifetime and hall data

We demonstrate that positron annihilation provides a direct method to separate vacancy-type and ion-type acceptors in p-type Cd0.22Hg0.78Te crystals. We show how to combine positron and Hall data to obtain the concentrations of acceptors, both types, and donors. In crystals with a low concentration of negative ions, there is clear evidence that the vacancies have two ionization levels 2-→1- and 1-→0.