INGAAS METAL-SEMICONDUCTOR-METAL PHOTODETECTORS WITH A HYBRID COMBINATION OF TRANSPARENT AND OPAQUE ELECTRODES

A metal-semiconductor-metal photodetector (MSMPD) with a hybrid combin ation of transparent cadmium-tin-oxide and opaque Ti:Au electrodes is proposed and demonstrated. A significant decrease in dark current is o btained by independently engineering the Schottky barrier heights at t he anode and cathode. In addition, the use of transparent electrodes e nables more light to be coupled into the front-side illuminated MSMPDs thereby increasing the responsivity. For an applied bias of 5 V, thes e devices exhibited an extremely low dark current density of 21.2 fA/m u m(2) and a high responsivity of 0.56 A/W to perpendicularly incident 1.31 mu m wavelength light. (C) 1997 American Institute of Physics.