Schottky contact on a ZnO (0001) single crystal with conducting polymer

High quality Schottky junctions were fabricated on a ZnO (0001) bulk single crystal by spin coating a commercial conducting polymer, poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), as the metal electrodes. The junctions exhibited excellent rectifying behavior with a typical ideality factor of 1.2. Such parameters as Schottky barrier height (phi(b)) and built-in potential (V-bi) show negligible variation among junctions. The electron affinity of ZnO derived from phi(b) and qV(bi) values show a slight deviation (similar to 0.2 eV), suggesting the existence of spontaneously formed interfacial dipole layer between ZnO (0001) polar surface and anionic PSS molecules. (C) 2007 American Institute of Physics.