POLARIZATION AND WAVELENGTH DEPENDENCE OF METAL-SEMICONDUCTOR-METAL PHOTODETECTOR RESPONSE

Photocurrent and transmission studies for,543<lambda<1523 nm of metal- semiconductor-metal (MSM) photodetectors on semi-insulating GaAs subst rates demonstrate a polarization and wavelength dependence of the coup ling of light into the metal electrodes. Devices with electrode period s of 400 and 800 MI were investigated and differences as large as 85% in efficiency between orthogonal polarizations were measured for the 4 00 MI devices. Modeling of the energy transmission through lamellar pe riodic structures using a Greens function formalism and incorporating dispersion of the substrate dielectric constant produces semiquantitat ive agreement with the measurements. Suggestions for future MSM photod etector design are discussed.