Structural and optical properties of Cu2ZnSnSe4 thin-films for photovoltaic applications

Cu2ZnSnSe4 thin-films are deposited with different sequential processes. The grain size and uniformity of the surfaces were different according to the process despite the final compositions are stoichiometric such as Cu poor and Zn rich measured by energy dispersive x-ray spectroscopy. X-ray diffraction studies reveal that the films have different secondary phases and preferred orientation depending on the process. The optical properties such as transmittance and reflectance indicate different ratio and wavelength. Local electrical properties using Kelvin prove force microscopy and conductive-atomic force microscopy yield the information of local surface potential and electrical transport.