Inhomogeneous electric field-induced Raman scattering at ZnSe/GaAs interfaces

The activation of inhomogeneous electric field-induced Raman scattering (IE FIRS) at ZnSe/GaAs interfaces is investigated. The consideration of the inh omogeneous character of the electric field brings additional conditions on top of those predicted by the microscopic and perturbative approaches. Thes e conditions concern the relative orientations of (i) the wave vector of th e vibrational modes in the matter, (ii) the direction of the electric field at the junction, and (iii) the gradient vector of the electric field magni tude in the space charge regions. As latter vector has opposite directions in the layer and the substrate, IEFIRS is only observed from one side of th e junction for a given scattering geometry. (C) 1999 American Institute of Physics. [S0021-8979(99)03604-X].