In situ investigation of the selenization kinetics of Cu–Ga precursors 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 CuGaSe2 formation from Cu–Ga 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 CuSe forms in the temperature range of approximately 260 to 370 °C, and the onset of formation of CuGaSe2 occurred at approximately 300 °C. The kinetic analysis using a modified Avrami model suggests the formation of CuGaSe2 from selenization of Cu–Ga films follows a one-dimensional diffusion-controlled reaction with an apparent activation energy of 109 (± 7) kJ/mol.