Raman spectroscopy study of AgGaSe2, AgGa0.9In0.1Se2, and AgGa0.8In0.2Se2 crystals

AgGaSe2, AgGa0.9In0.1Se2, and AgGa0.8In0.2Se2 single crystals grown by the horizontal Bridgman technique were studied utilizing Raman spectroscopy excited with 633- and 784-nm lasers at temperatures varied from 77 to 300 K. The resonant Raman scattering associated with a transition from the Gamma(6)(B) of the valence band to the conduction band Gamma(6) of AgGa(0.9)In(0.1)Se(2)crystal is demonstrated. Resonant enhancements of the longitudinal optical (LO) polar modes of Gamma(5) (or E) including Gamma(5L)(W-4), Gamma(5L)(W-3), Gamma(5L)(X-5), and Gamma(5L), (Gamma(15)), and their overtones and combinations in the crystal at 77 K were observed. (C) 2010 Elsevier Ltd. All rights reserved.