Abstract

The use of gratings to couple optical energy into surface plasma wave modes that are confined to a dielectric-metal interface has been extensively explored. We report on the first use of this coupling to enhance the quantum efficiency of internal photoemission detectors on III-V semiconductors. In this type of device, hot carriers are generated in a metal film by optical absorption and are collected by internal photoemission over a Schottky barrier into the semiconductor. For our initial experiments, the Au-(p-InP) system was used. Gratings, 25-100 nm deep, with a period of 2 μm and a line/space ratio of ~ 1/3 were fabricated photolithographically on heavily doped (~ 1 × 10¹⁸ cm⁻³) p-InP (see inset to Fig. 1). Au films, 25-100 nm thick, were evaporated to form the Schottky barriers; the device active area was 1.6 × 10⁻⁴ cm².

© 1985 Optical Society of America