Ultrafast Surface Barrier Photodetectors

We present results of an investigation into interdigital Schottky barrier photodetectors, using silicon-on-sapphire as an exemplary material. The steady-state and pulsed characteristics of the devices have been studied, both theoretically and experimentally, with good agreement being found in both regimes. In particular, the effective carrier lifetime in the material was found to be approximately 400 psec, and the response time of a small area device was found to be less than 30 psec. In addition, for purposes of comparison, some measurements are reported using this structure on bulk silicon.