Mechanism for conversion of the conductivity type in arsenic doped p-CdxHg1–xTe subject to ionic etching

Abstract

Based on an analysis of chemical diffusion of mercury in p-CdxHg1–xTe:As narrow-band solid solutions, a mechanism for conversion of the conductivity type upon ionic etching is suggested. It is shown that the n–p conversion of the conductivity in this case is due to the formation of a donor complex between arsenic in the Te sublattice and an interstitial Hg atom. Moreover, the electron concentration in the converted layer corresponds to the concentration of the implanted arsenic impurity. The theoretical results are confirmed by the experimental investigation of the electron concentration distribution over the n-layer of a p-CdxHg1–xTe:As epistructure converted upon ionic etching.