Optical absorption edge of TlIn1 − xGaxSe2 solid solutions

We have studied the optical absorption edge of TlIn1 − x Ga x Se2 (x = 1.0, 0.9, 0.7, 0.6, 0.5) solid solutions, identified the types of the observed optical transitions, and evaluated the band gap of the solid solutions and the energy of phonons involved in the transitions.