Characterization of phases and determination of phase relations in the Cu-In-S system by γ-γ perturbed angular correlations

Abstract

Perturbed angular correlations (PAC's) of \ensuremath{\gamma} rays are applied to phase identification and determination of phase relations in the Cu-In-S system at room temperature. Using metallic indium, containing radioactive $^{111}\mathrm{\ensuremath{-}}^{111}$Cd tracers, as starting material, various single and multiphase samples of chosen compositions were grown from the melt and characterized by PAC's. Thus, we identified three Cu-In phases, the In-S phase ${\mathrm{In}}_{6}$${\mathrm{S}}_{7}$, and the ternary phases ${\mathrm{CuIn}}_{5}$${\mathrm{S}}_{8}$ and ${\mathrm{CuInS}}_{2}$ by means of their PAC signals. When combined with the already known PAC parameters of ${\mathrm{CuIn}}_{2}$, In, InS, and ${\mathrm{In}}_{2}$${\mathrm{S}}_{3}$, these data constitute a complete description of all room-temperature phases of the Cu-In-S system which contain In. PAC measurements of the multiphase samples show that no further In phases exist and allow the determination of several equilibrium lines in the Gibbs phase triangle. Consequences for the crystal growth of ${\mathrm{CuInS}}_{2}$ are discussed.