Electrical properties of ZnP2 single crystals of tetragonal and monoclinic modifications

Abstract

Measurements are made of the electrical properties of both modifications of ZnP2 crystals, which are doped, undoped, and annealed in vacuum and in the vapour of the components. The measurements are carried out in the temperature range from 190 to 380 K. It is found that in the crystals of tetragonal (α) modification there are two acceptors at (Ev + 0.47) eV and (Ev + 0.21) eV and a donor at (Ec - 0.36) eV. In the crystals of monoclinic modification an acceptor at (Ev + 0.30) eV is established. By means of thermal treatment of the crystals these acceptor centres are shown to be intrinsic defects of singly and doubly charged zinc vacancies. The donor centres are found to be vacancies of phosphor. The dominating scattering mechanism is the scattering on ionized defects in the temperature range under investigation. From the experiments the concentrations of donor and acceptor centres for initial α-crystals are found to be equal to ND = −4.9 × 1021 m−3, NA = 6.0 × 1021 m−3 and for initial β-crystals ND = 4.6 × 1022 m−3, NA = −6.2 × 1022 m−3. The investigation of electrical properties of the doped crystals shows that the mechanism of the impurity intrusion corresponds to the well known model. [Russian Text Ignored].