Structural, photovoltaic and optoelectronic properties of graphene–amorphous carbon nanocomposite

Reduced graphene oxide–amorphous carbon nanocomposites were coated on p-Si wafers to prepare graphene-based photodiodes or photodetectors. Electrophoretic deposition was used to prepare electronic devices. Scanning electron microscopy, energy-dispersive spectra, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used in the morphological and structural characterization. Characterization methods confirm that deposited films are in reduced graphene oxide–amorphous carbon nanocomposite structure. Photoresponsive characteristics were checked using I–V, I–t and C–t techniques. It was seen that diodes are responsive to illumination where increased photocurrent and photocapacitance were obtained for increased illumination intensity. Electrical properties were assessed; C–V, G–V properties were found to depend on AC signal frequency. Signal frequency-dependent behavior was attributed to interface states. The density of interface states was calculated, and it was seen that the density of interface states increases with increasing AC signal frequency. It was illustrated that electrical characteristics of photodiodes were affected by signal frequency and the density of interface states.