Metal Semiconductor Interfaces

Origin of Schottky Barriers in Gold Contacts on GaAs(110) [Phys. Rev. Lett. 93, p.206801 (2004)]

Gold contacts on n-type GaAs(110) have been investigated using Scanning Tunneling Microscopy and Spectroscopy in cross-sectional configuration. In spatially-resolved current voltage spectroscopy the Schottky barrier potential is visible. We find signatures of delocalized gap states at the interface decaying into the semiconductor and observe a defect density at the interface below 3 * 10^13 cm -2. Both findings support that the Fermi level pinning at the Au/GaAs(110) interface is dominated by metal-induced gap states.

Our work (Göttingen) is supported by the Deutsche Forschungsgemeinschaft (DFG) within SFB 602 (TP A7).