Raman scattering from GaSe1−xTex

The long-wavelength optical phonons of the layer GaSe1-xTex have been investigated at room temperature by means of Raman scattering spectroscopy. The spectra of the Bridgman grown crystals were excited with the 1.06 mu m line of the continuously operated YAG:Nd3+ laser. Detailed study of the Raman spectra of GaSe1-xTex solid solutions showed that there is an abrupt change in the frequency-composition dependences for all observed modes. It is shown, that a phase transition from hexagonal epsilon -GaSe to monoclinic GaTe in GaSe1-xTex solid solutions takes place in the composition range 0.27 < = x < = 0.72. Only one mode behaviour of the optical phonons was observed in GaSe1-xTex system. 12 ref.--AA