Photodiodes based on graphene oxide–silicon junctions

Schottky barrier diode based on graphene oxide (GO) with the structure of Al/GO/n-Si/Al was fabricated. The current–voltage characteristics of the diode were investigated under dark and various light intensity. It was observed that generated photocurrent of the diode depends on light intensity. Various junction parameters were presented using I–V characteristics. The transient photocurrent measurement indicated that the Al/GO/n-Si/Al diode was very sensitive to illumination. The photocurrent of the diode increases with increase in illumination intensity. The capacitance–voltage–frequency (C–V–f) measurements indicated that the capacitance of the diode depends on voltage and frequency. The capacitance decreases with increasing frequency due to a continuous distribution of the interface states. These results suggest that the Al/GO/n-Si/Al diode can be utilized as a photosensor.

► Nanostructured thin film of graphene oxide is deposited on n-silicon substrate.
► The ideality factor and barrier height of the Al/GO/n-Si/Al diode were obtained to be 2.94 and 0.50 eV, respectively.
► The photocurrent in the reverse bias voltage is increased by increasing photo-illumination intensity.
► The Al/GO/n-Si/Al diode can be used for optical sensor applications.