Journal of the electrochemical society vol:148 issue:11 pages:C733-C739
The electrochemical deposition of bismuth on n-GaAs(100), n(+)-GaAs(100), and p-GaAs(100) from Bi(NO3)(3) solution is characterized by cyclic voltammetry and impedance measurements. Electron capture at the conduction band forms the rate-determining step in the reduction of Bi3+ at n-type GaAs. The morphology of the bismuth films is related to the deposition kinetics. The rectifying n-GaAs/Bi Schottky barrier formed on low-doped substrates prevents oxidation of bismuth, whereas tunneling through the space-charge layer allows anodic stripping of Bi on highly doped substrates. Under illumination, electroless deposition of Bi is observed on n-GaAs. Surface-state mediated hole injection is responsible for the slow deposition of Bi on p-GaAs in the dark. Photoassisted nucleation and subsequent growth in the dark results in the formation of continuous thin Bi films on p-GaAs. (C) 2001 The Electrochemical Society.