OPTICAL PHONONS IN LASER-DEPOSITED CDSXTE1-X FILMS

We report the longitudinal optical (LO) phonon frequencies for thin fi lms of the ternary alloy CdSxTe1-x and their composition dependence fo r the full range of x values from pure CdTe to pure CdS. Pulsed laser deposition was used to prepare the polycrystalline thin films includin g compositions well inside the miscibility gap. We find that this tern ary system exhibits a ''two-mode'' behavior with CdS- and CdTe-like lo ngitudinal optic phonon modes. The modified random-element isodisplace ment model yields a good description of the composition dependence of the LO phonon frequencies. (C) 1997 American Institute of Physics.