Особливості електричних характеристик напівізолюючих кристалів CdTe-Сl

Electrical properties of semi-insulating CdTe-Сl crystals, grown by the vertical Bridgman and the travelling heater method, have been studied. It is found that the travelling heater method provides electron conductivity of the crystals, and the vertical Bridgman method – hole conductivity. Specific resistance of the samples is of (108-109) Ohm×сm at 300 K, and Hall mobility of the holes and electrons is of (45 - 55) cm2/V·s and (10 - 20) cm2/V·s respectively. Very low values of electron mobility and an exponential temperature dependence of µn are due to drift barriers with a height of eb ≈ 0.20 eV. Formation of the barriers is caused by the fluctuations of the potential relief resulting from the microheterogeneity of the defect-impurity system. Quasi-photochemical reactions that reduce electron mobility after photo-excitation have been observed in n-CdTe-Cl samples. In p-CdTe-Cl samples, neither drift barriers, nor quasi-photochemical reactions were detected.