Reaction kinetics of a-CuInSe2 formation from an In2Se3/CuSe bilayer precursor film

The reaction pathway and kinetics of a-CuInSe2 formation from a glass/In2Se3/CuSe polycrystalline bilayer precursor film were investigated using time-resolved, in situ high-temperature X-ray diffraction. Bilayer glass/In2Se3/CuSe precursor films were deposited on thin glass substrates in a migration enhanced molecular beam epitaxial deposition system. These films were then temperature ramp annealed or isothermally soaked while monitoring the phase evolution. The initial In2Se3 and CuSe reactant phases were directly transformed to a-CuInSe2 without any detectable intermediate phase. Kinetic parameters were estimated using the Avrami and parabolic diffusion controlled reaction models. The parabolic reaction model fitted the experimental data better than the Avrami model over the entire temperature range (230–290 8C) of the set of isothermal experiments, with an estimated activation energy of 162 (G5) kJ/mol. q 2005 Elsevier Ltd. All rights reserved.