We present a new characterization method for traps at the interfacial layer of Schottky contacts. This method is based on ac-admittance measurements and a new trap transistor model which quantitatively explains the measured ac behavior as well as the dc characteristics. In particular we propose the ac current across the interface to consist of capacitive as well as of conductive parts. We apply the analysis to Au/GaAs Schottky contacts and find a weak energy dependence for the density of interface states in the band gap of GaAs.

• Received 3 March 1986

DOI:https://doi.org/10.1103/PhysRevLett.57.1080