Temperature dependence of phonon modes, dielectric functions, and interband electronic transitions in Cu2ZnSnS4 semiconductor films
Abstract
The quaternary semiconductor Cu2ZnSnS4 (CZTS) has attracted a lot of attention as a possible absorber material for solar cells due to its direct bandgap and high absorption coefficient. In this study, photovoltaic CZTS nanocrystalline film with a grain size of about 10 nm has been grown on a c-plane sapphire substrate by radio-frequency magnetron sputtering. With increasing the temperature from 86 to 323 K, the A1 phonon mode shows a red shift of about 9 cm−1 due to the combined effects of thermal expansion and the anharmonic coupling to the other phonons. Optical and electronic properties of the CZTS film have been investigated by