Identification of the double acceptor levels of the mercury vacancies in HgCdTe

Abstract

Photoluminescence and temperature-dependent Hall measurements of nonintentionally doped HgCdTe epilayers were compared. These films were grown by liquid phase epitaxy and postannealed under different conditions as follows: a p-type annealing was used to control the mercury vacancy concentration and a n-type annealing under saturated Hg atmosphere was used to fill the mercury vacancies. The comparison of the photoluminescence measurements with Hall effect measurements allows us to identify the two acceptor energy levels of the mercury vacancy and to evidence its “negative-U” property corresponding to a stabilization of the ionized state V− of the mercury vacancy compared to its neutral state V0.