OPTOELECTRONIC EFFECTS IN P-CDGEAS2 SINGLE-CRYSTALS AND STRUCTURES BASED ON THEM

Spectra of inelastic light scattering by optical phonons in p-CdGeAs2 single crystals were obtained for the first time. The observed clear p olarization dependence and the absence of any appreciable dependence o f the intensity and frequency of the observed lines when the sample is swept in approximate to 300 mu m steps indicates these CdGeAs2 single crystals grown by directional crystallization from a near-stoichiomet ric flux, are of high quality and homogeneous. The type of symmetry of the observed phonon lines is interpreted and it is shown that the for ce constants in CdGeAs2 and CdSnP2 crystals differ slightly. Temperatu re dependences of the electrical conductivity and the Hall constant we re studied in oriented homogeneous p-CdGeAs2 single crystals. It was e stablished that the conductivity of these crystals is determined by th e deep acceptor level E-A=0.175 eV and has the degree of compensation 0.5-0.6. The temperature dependence of the Hall mobility reflects the competition between impurity and lattice mechanisms of hole scattering . The photosensitivity of In/CdGeAs2 surface barrier structures reache s 20 mu A/W at T=300 K and remains at this level within the fundamenta l absorption of CdGeAs2. It is concluded that these structures may be used as wide-band photoconverters for natural light and as selective p hotoanalyzers for linearly polarized radiation. (C) 1998 American Inst itute of Physics.