Selective formation of Ohmic junctions and Schottky barriers with electrodeposited ZnO

Abstract

Constant-potential electrochemical synthesis of ZnO on metal substrates enables selective formation of either Ohmic or Schottky-barrier contacts. Using a mildly acidic nitrate-based aqueous electrolyte, there is a substrate-dependent deposition potential below which electrodeposited ZnO heterojunctions display Schottky response with high contact resistances (∼ 105 ) and above which Ohmic behavior and low contact resistances (∼1 ) occur. Voltammetric evidence for Zn metal deposition, in conjunction with Schottky-barrier heights that are consistent with values expected for a ZnO-Zn junction, suggests that more negative deposition potentials create a Zn-based interface between the substrate and ZnO that leads to rectifying behavior. © 2008 American Institute of Physics.