RAMAN-SPECTROSCOPIC STUDY OF THE H-C-AS COMPLEX IN EPITAXIAL ALAS

H-C-As pairs in epitaxial layers of AlAs have been studied by local vi brational mode (LVM) Raman spectroscopy and complemented by infrared ( IR) absorption measurements performed on the same samples. Inelastic l ight scattering by the symmetric A(1)(+) mode (X), the antisymmetric A (1)(-) mode (stretch) and the 'carbon-like' antisymmetric E(-) mode (Y -2) was detected and the mode frequencies were found to be in good agr eement with the IR absorption measurements. All four isotopic combinat ions of H(D) and C-12/C-13 were detected for the X and stretch modes, but only three of the E(-) modes (Y-2) were detected since the Y-12(2) H line was obscured by second-order scattering from To(X) phonons. Pol arization-dependence Raman measurements allowed mode symmetries to be determined for the first time, confirming previous assignments of the LVMS Of H-C-As pairs observed by IR absorption.