Symmetrical Mott barrier as a fast photodetector

A novel surface-oriented GaAs punch-through photodetector possessing a fast photoresponse and a moderate internal gain is described. The device has a simple planar MnM structure consisting of two Schottky contacts which thereby facilitate the fabrication. The detector exhibits an internal rise time as fast as 20 ps with a full width at half maximum (FWHM) of 35 ps. The internal gain of the detector was estimated to be 3. The noise equivalent power was measured to be 4×10¿11 W/¿Hz. The detector represents one of the fastest GaAs photodetectors reported to date.