T- x phase diagram of the TlGaS-TlFeS system and band gap of TlGaFeS (0 ≤ x ≤ 0.01) single crystals.

We have constructed the T- x phase diagram of the TlGaS-TlFeS system (simple eutectic system, eutectic at 80 mol % TlFeS with a melting point of 953 K). The system contains limited series of monoclinic solid solutions based on the ternary end-members. At an annealing temperature of 933 K, the TlGaS-based solid solution extends to 5 mol % TlFeS and the TlFeS-based solid solution extends to ≅10 mol % TlGaS. We have examined the effect of partial iron substitution for gallium on the optical properties of melt-grown single crystals of the TlGaS-based solid solutions and determined their band gap as a function of temperature and Fe concentration. [ABSTRACT FROM AUTHOR]