In situ investigation on selenization kinetics of Cu–In precursor using time-resolved, high temperature X-ray diffraction

In situ high-temperature X-ray diffraction was used to investigate the reaction mechanism and kinetics of α-CuInSe2 formation from Cu–In precursors during selenization. The precursor films were deposited in a migration-enhanced molecular beam epitaxial reactor on Mo-coated thin glass substrates. During the selenization, the formation of CuSe was observed, followed by its transformation to CuSe2 at higher temperature. The formation of α-CuInSe2 was initiated at a temperature between 250 and 300 °C. Additionally, the production of MoSe2 was clearly detected at temperatures above 440 °C. The reaction kinetics were analyzed using both the Avrami and parabolic rate models to estimate diffusion-limited activation energies of 124 (±19) and 100 (±14) kJ/mol, respectively.