The phase diagram of the quasibinary system Ga2Te3/Ga2Se3

The quasibinary system Ga2V(Se3/Te(3-3l)) that forms at high temperatures a continuous range of solid solutions shows the special property that the lattice constants can be changed continuously maintaining a constant high vacancy density. In order to know in which temperature region this can be achieved, the phase diagram including miscibility gaps, ordering regions and melting behavior should be known. The quasibinary system Ga2Te3/Ga2Se3 was investigated by X-ray phase analysis and by DTA. The system forms extended regions of solid solutions. The phase diagram can be modelled by a Gibbs energy function for a subregular system with ordering tendencies. From the excess Gibbs energy function the thermodynamic factor for interdiffusion can be calculated.