Abstract

Metal-semiconductor-metal (MSM) photodiodes on GaAs are attractive detectors for the 800 nm communications wavelength range because of their large bandwidth, high sensitivity, and integrability with existing GaAs FET transistor technology. Experimental and theoretical work has defined the role of electrode geometry and substrate material in determining device speed and responsivity.^1,2 Here we present studies that indicate MSM photodiodes have an inherent polarization dependence and that diffraction plays an important role in determining the photo-excited carrier distribution. We have also investigated the use of heterostructure geometries to increase speed in the near IR without significantly sacrificing device efficiency.³

© 1993 Optical Society of America