Study of Copper Tin Selenide Nanoparticles of Milled Powder and Thin Films

Nanoparticles Cu2SnSe3 alloys were synthesized by mechanical alloying from mixtures of pure crystalline Cu, Sn and Se powders using a low cost planetary ball milling process optimizing the milling duration and the rotational speed. The properties of Cu2SnSe3 (CTSe) thin films deposited by thermal evaporation from this powder on glass substrate at Ts = 400°C were investigated. Powders and films were analyzed by X-ray diffraction (XRD), scanning electron microscopy(SEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM), to determine their microstructure, morphology, chemical compositions and root-mean-square (RMS) roughness. XRD analysis revealed that all samples crystallize in polycrystalline nature with cubic structure and lattice parameter a = 5.68 Å. The optical measurements were carried out in the [500-2500nm] wavelength range and were determined from spectral transmission data. Optical measurements showed that the deposited layers had a relatively high absorption coefficient of 104 cm-1 and the direct energy band gap was found to be around Eg =1.29eV. The suitable p-type conductivity of CTSe thin films was confirmed by hot probe method. Other electrical parameters (carrier concentration np = 10.04x1018 cm-3, electrical resistivity ρ = 30.49x10-2 Ω cm and mobility μH = 94.33 cm2/V s) were measured at room temperature.