Compensated donors in semi-insulating Cd1−xMnxTe:In crystals

Abstract

The temperature dependences of electrical characteristics (conductivity σ, the Hall constant RH, and carrier mobility μ) were studied in n-Cd1−xMnxTe:In (x = 0.05; 0.1) crystals grown by the Bridgman method. Reproducibility of electrical characteristics was achieved by thermal treatment at 420 K for 1 h. The RH(T) dependence was characterized by the exponential high- and low-temperature regions with different activation energies. The activation energy in the high-temperature region of RH(T) corresponds to the ionization energy εD of the donors controlling n-type conductivity. The activation energy ε1 in the low-temperature region of RH(T) is related to εD by the relation ε1 = εD − γεb, where γ-factor is close to 1 and εb is activation energy, which determined the temperature dependence of carrier mobility in the low-temperature region. The presence of this region is due to micro-inhomogeneities, which are formed during post-growth cooling of the crystal.