n-ZnO film has been formed on p-Si substrate using sol–gel spin-coating technique. For structural, optical and morphological characterization, the XRD pattern, SEM images and EDX spectra of the n-ZnO film have been obtained. The optical band gap of n-ZnO has been calculated as 3.29 eV. A Schottky diode application of the film has been performed by evaporation of Au on n-ZnO film. It has been seen that the device has exhibited good rectifying behavior. The current–voltage (I–V) and capacitance–voltage (C–V) measurement of the device has been taken as a function of the frequency, at room temperature. Using I–V curve, the ideality factor and barrier height (Φ<inf>b</inf>) of n-ZnO have been calculated as 1.93 and 0.80 eV, respectively. (Φ<inf>b</inf>) (C–V) has been found 0.86 eV, at 500 kHz frequency.