Passivation of pinned n-GaAs surfaces by a plasma-polymerized thin film

Abstract
The passivating effects of the plasma‐polymerized thiophene thin film on the intrinsic properties of n‐GaAs surfaces have been investigated by means of scanning electron microscopy–electron beam induced current and capacitance‐voltage techniques. Reduction of the surface recombination velocity and the surface barrier at the interface between polymer and GaAs has been reported. These results indicate that the Fermi level is no longer pinned at midgap, but is moved closer to the conduction band. We discuss a possible unpinning mechanism.