The Raman spectrum of gallium phosphide

Abstract

The first and second-order Raman spectra of gallium phosphide recorded recently by Russell and Hobden using a He-Ne laser source, are discussed in the light of current theories on the dynamics of crystal lattices. The observed spectra of GaP is examined in detail with a calculation of the phonon frequencies from the critical points Γ, L and X, using the Raman supercell modes and their frequency expressions as given by Ramanathan for ZnS lattice. Satisfactory explanations have been given for the observed second-order frequencies in the case of GaP.