ELECTRONIC, CRYSTALLOGRAPHIC AND SPIN-POLARIZED PROPERTIES OF DOPED CDSIAS2 SINGLE-CRYSTALS

Properties of CdSiAs2 single crystals (up to 15 x 6 x 5 mm3), in-situ doped with In, Au, Ag, Cd, Cu, Al and B during CVT growth, are reported. Net hole carrier densities between 3.9 x 10(13) and 2.4 x 10(13) cm-3 were obtained at room temperature. Doping concentration, determined by chemical analysis, resistivity, Hall mobility and activation energy are discussed. Doping with In results in n-type CdSiAs2 crystals with a donor level at E(C) = 630 meV. This result corresponds to the model, in which In acts as donor on a Cd site. A photoluminescence spectrum of the Al-doped crystal is shown. High resolution X-ray diffraction revealed a FWHM of 16 are sec for rocking curves at the (112) plane. Oriented single crystals (Al-doped with p = 2 x 10(18) cm-3) were used successfully as a source of spin-polarized electrons reaching a maximum polarization of 25% at 2.2 eV. Possibilities why the theoretical value of 100% electron spin polarization could not be observed, are discussed. The B transition (GAMMA-6-v - GAMMA-6-c) was detected at 1.75 eV by the change of sign of the polarization at room temperature.