Kinetics of electron charging and discharging on embedded W disks in GaAs

Electron-capture and -emission processes in nanometer-sized Schottky contacts on a floating potential have been studied experimentally. Arranged patterns of tungsten disks have been embedded in GaAs by epitaxial overgrowth and a buried semi-insulating layer is created by overlapping depletion regions from the individual disks. We have investigated the embedded metal-semiconductor contacts by space-charge techniques. We demonstrate how these buried contacts can be characterized optically and electrically, and that the metal disks may be charged and discharged in a controlled way. The data reveal the difference between single- and multiple-electron processes.