The properties and application of gallium nitride (GaN) films grown on silicon at a low temperature (873 K) by electron cyclotron resonance (ECR) plasma-assisted metalorganic chemical vapor deposition (MOCVD) were investigated. Structural analysis revealed microcrystalline structure (muc-GaN) with crystallite size of 167 nm for these smooth and transparent films. Ni/muc-GaN metal-semiconductor-metal (MSM) photodiode have been fabricated and analyzed by means of electrical characterization, using current-voltage (I-V) and capacitance-voltage (C-V) measurements to evaluate the Schottky contact parameters for the study of current transport mechanism of the MSM photodiode. The barrier height Ob determined from the C-V method is 0.734 eV. (C) 2004 Elsevier B.V. All rights reserved.