Couples were used to study the kinetics of intermediate phase development, and the associated phase equilibria. In the case of couples which were annealed at 550C for 1.5h, all of the phases on the Cu2Se-In2Se3 pseudo-binary phase diagram cross-section appeared; including CuInSe2. The In6Se7 phase formed at annealing times longer than 1.5h at 550C. This indicated a departure of the diffusion pathway from the pseudo-binary phase diagram cross-section. Precipitates of CuInSe2, with a dendritic morphology, were also produced far from the initial interface. This indicated that In was the fast component during interdiffusion.

CuInSe2 Phase Formation during Cu2Se/In2Se3 Interdiffusion Reaction J.S.Park, Z.Dong, S.Kim, J.H.Perepezko: Journal of Applied Physics, 2000, 87[8], 3683-90