Photoconductive Diodes

Abstract

The photoconductive circuit element (PCE), or photoconductive diode, can detect optical signals and convert them to electrical signals. It can be switched on and off rapidly by using an optical source, it can be made fairly compact, and it can conduct large currents in the on state and hold off high voltages in the off state (Auston, 1984). As a result, the PCE is useful in high-speed switching (Frankel et al., 1990), in establishing optical links between circuits (Lee, 1990), and is an attractive alternative or supplement to the high-power mechanical switchgear currently used in the electric utility industry (Triaros et al., 1990). In order to minimize commutation energy losses in PCEs, the inductance in these devices must be reduced. Silicon has been widely used in PCE fabrication because it offers low cost, small circuit inductance, high thermal conductivity, and enhanced power density rating, all of which are critical to switching applications (Rose, 1963).