Ion-beam-induced modification of the electrical properties of vacancy-doped mercury cadmium telluride

The effect of ion-beam milling (IBM) on the electrical properties of vacancy-doped mercury cadmium telluride (MCT) p-Hg_1−x Cd _x Te (x ∼ 0.22) has been studied. The samples were prepared by thermal annealing of molecular beam epitaxy (MBE)-grown heterostructures and the films and single crystals grown by liquid-phase epitaxy (LPE). The etching of samples by IBM resulted in the formation of donor centers. In MBE-grown heterostructures (but not in LPE-grown samples), the concentration of these centers reached ∼10¹⁷ cm⁻³. It is established that the appearance of a high concentration of donor centers in the heterostructures is caused by the IBM-induced activation of neutral defects formed during epitaxial growth. The probable nature of defects is discussed.