Estimation of Co2+ solubility limit in CdTe from lattice parameters, magnetization and spectroscopic characterization

Single crystals of Cd1-x Cox Te ternaries, grown by the vertical Bridgman t echnique, are characterized with x-ray diffraction, electron microprobe ana lysis, wavelength modulated reflectivity, resonant Raman scattering and mag netization measurements. The lattice parameter decreases linearly with incr easing x in the range 0 less than or equal to x less than or equal to 0.022 , but not beyond. The Co2+ concentration estimated from magnetic measuremen ts as well as that from microprobe analysis reveals a maximum value of x si milar to 0.02, significantly higher than that reported in the literature, s uggesting 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 subs titutional incorporation of Co2+ in CdTe.