Raman studies of Ball mill synthesized bulk Cu2ZnSnSe4

Kesterite with chemical formula Cu2ZnSnSe4 (CZTSe) has been synthesized by ball milling followed by annealing and hot pressing. Mechanochemical synthesis was carried out in the presence of process control agent namely toluene under two different milling conditions. Structural and phase evolution during different stages of the synthesis was studied with X-ray diffraction (XRD) and Raman spectroscopy. Near resonant Raman spectrum was obtained by making use of laser wavelength of 488 nm to resolve the presence of secondary ZnSe which otherwise is difficult to conclude with XRD alone. Deconvoluted Raman spectrum confirmed the presence of CZTSe along with secondary phases Cu2SnSe3 (CTSe) and ZnSe. This inference was further confirmed by electron probe micro analysis (EPMA) and wavelength dispersive spectroscopy (WDS) studies.