ZnO photoconductive sensors epitaxially grown on sapphire substrates

We report the fabrication of ZnO photoconductive sensors epitaxially grown on sapphire substrates with interdigitated Ni/Au electrodes. It was found that there exists an electric field-dependent photoconductive gain in the fabricated sensors. With an applied electric field of 500 V/cm, it was found that maximum quantum efficiency was around 2.8% while time constant of the decay transient was τ ∼ 0.556 ms. © 2007 Elsevier B.V. All rights reserved.