Study of the effect of polarity and of dislocations on the electrical and optoelectronic properties of p-type Cd0.96Zn0.04Te

The effect of polarity and of dislocations on the electrical and optoelectronic properties of p-type Cd0.96Zn0.04Te grown by the horizontal Bridgman method is studied from I(V) and C(V) measurements performed before and after indentation. Measurements under illumination are achieved using an original set-up coupled to an automatic one used for I(V) and C(V) measurements. The method used for plastic deformation is Vickers microhardness. A suitable surface preparation of the samples has enabled ohmic contacts to be made using electroless gold, and Schottky contacts by In evaporation. Better diodes are produced on the Cd face, consistent with the leakage currents and surface state densities being lower on this face than on the Te one. Dislocations induced in the crystal lead to the creation of acceptor centres attributed to Cd vacancies. The photoconductivity decrease after indentation is interpreted in terms of a decrease of the mobility of electrons through their interaction with the dislocations created, and in the electron concentration as a result of surface recombination. (C) 2000 Elsevier Science B.V. All rights reserved.