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.

Polarity inversion and coupling of laser beam induced current in As-doped long-wavelength HgCdTe infrared detector pixel arrays: Experiment and simulation

“…18,19 However, in As-doped HgCdTe, the arsenic may reside on either the metallic sublattice thus behaving as a donor or the nonmetallic sublattice thus acting as an acceptor. 20 Specifically, when used on a long wavelength HgCdTe infrared detector, As-doped p-type HgCdTe is very sensitive to temperature. This amphoteric behavior, together with the ion implantation damage and mixed conduction, could potentially induce a deformation of the LBIC.…”

“…It is well known that As-doped p-type HgCdTe layer can transition to an n-type layer at near room temperature. 20,21 This amphoteric behavior, together with the mixed conduction of HgCdTe due to the temperature-generated large numbers of intrinsic carriers, makes the p-type absorption layer transform to an n-type layer. Several groups, [22][23][24] using deep-level transient spectroscopy as well as dark current fitting, 7,11,25 have reported that the damage of the ion implantation doping can introduce significant deep level traps in HgCdTe.…”