Abstract
The intersubband resonance absorption enhanced by the insulator-semiconductor interfacial irregularities in a metal-insulator-semiconductor system is investigated theoretically. The line shape of absorption spectrum is calculated microscopically. It is shown that the perpendicular excitation can be effectively generated by electric fields parallel to the surface due to the localized electromagnetic waves scattered by the surface irregularities. The general spectra for both isotropic and anisotropic surface scattering models are calculated and discussed.