Raman spectroscopy study of , , and 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 Γ 6 (B) of the valence band to the conduction band Γ 6 of AgGa0.9In0.1Se2crystal is demonstrated. Resonant enhancements of the longitudinal optical (LO) polar modes of Γ 5 (or E) including Γ 5 L ( W 4 ) , Γ 5 L ( W 3 ) , Γ 5 L ( X 5 ) , and Γ 5 L ( Γ 15 ) , and their overtones and combinations in the crystal at 77 K were observed.