Enhanced quantum efficiency internal photoemission detectors by grating coupling to surface plasma waves

Abstract

Enhanced quantum efficiencies have been obtained for Au-InP internal photoemission detectors using grating coupling of incident radiation into surface plasma waves confined to the air-metal interface. Enhancements of over a factor of 30 are observed at the resonance coupling angles. A model calculation of the surface plasma wave coupling is in good qualitative agreement with the experiment. Time-resolved response measurements show that the present detectors are capacitance limited; picosecond response speeds are attainable with lower carrier concentration materials and smaller active areas.