Microscopic Origin of Electrical Compensation in Arsenic-Doped HgCdTe by Molecular Beam Epitaxy: Density Functional Study

Abstract

The understanding of the configurations of the arsenic tetramer (As t ), dimer (As d ), and singlet (As s ) is important to explain the high electrical compensation of molecular beam epitaxy (MBE) samples and the conversion to p-type behavior. In this work, the possible configurations were optimized from density functional calculations for arsenic defects As n (n = 1, 2, and 4) in as-grown HgTe. According to the dominant electronic contribution to the defect formation energies, which was calculated under Te-rich conditions, the most probable configurations for As t , As d , and As s have been established. The above discussion applies to the neutral arsenic defects. A further study is necessary to consider the entropy contribution to the defect formation energy.