ENERGETICS OF VHg-RELATED DEFECTS IN As-DOPED HgCdTe

Abstract

Arsenic-doped HgCdTe usually exhibits compensated n-type conductivity, which is ambiguously attributed to isolated vacancies (V Hg ) or arsenic-vacancy complexes ( As Hg – V Hg and As Hg –2V Hg ). Our first-principles calculations clarified the correlation of these V Hg -related defects with the carrier compensation in As -doped HgCdTe by calculating the defect formation energies, as a function of atomic/electron chemical potentials. Under n-type condition, the lowest formation energy defect is found to be the As Hg donor followed by the V Hg acceptor, leading to a compensated n-type material. The arsenic-vacancy complexes are shallow acceptors but their high formation energies render them unlikely to be the compensating candidates. Their large binding energies, however, allow us to predict that the formation of the As Hg –2V Hg complex defect will be enhanced under postgrowth annealing treatment, in agreement with the arsenic activation model by Berding et al. [J. Electron. Mater.27, 605 (1998)].