Estimation of Co<SUP>2+</SUP> solubility limit in CdTe from lattice parameters, magnetization and spectroscopic characterization

Single crystals of Cd1-xCoxTe ternaries, grown by the vertical Bridgman technique, are characterized with x-ray diffraction, electron microprobe analysis, wavelength modulated reflectivity, resonant Raman scattering and magnetization measurements. The lattice parameter decreases linearly with increasing x in the range 0&#8804; &#215; &#8804; 0.022, but not beyond. The Co2+ concentration estimated from magnetic measurements as well as that from microprobe analysis reveals a maximum value of x~0.02, significantly higher than that reported in the literature, suggesting that it is indeed the solubility limit of Co2+ in CdTe. The blue shift of the excitonic energy gap with increasing x, observed in wavelength modulated reflectivity and in resonant Raman scattering, confirms the substitutional incorporation of Co2+ in CdTe