A High-Performance UV-Visible-NIR Broadband Photodetector Based on Si/PtSi/ TiO2/Graphene by the Photogating Effect

The photogating effect in graphene photodetectors is a reliable and promising approach for photodetectors with high responsivity. Graphene photodetectors based on the photogating effect usually work at a specific wavelength depending on the type of absorbing material. However, here we fabricated a new structure of the photogating photodetector working in the ultraviolet (UV), visible, and near-infrared (NIR) wavelengths at room temperature. A Si/PtSi/TiO2/Graphene heterostructure was designed and fabricated as a broadband photodetector with high responsivity. The responsivity of the photodetector is 5, 6.6, 9.1, and 0.64 A/W in the constant optical power of 0.1 mW in the wavelengths of 407, 650, 1310, and 1550 nm. In addition to, the rise times of the photodetector showed its superior performance. The rise time of the photodetector is 400, 210, 300, and $350 \mu \text{s}$ in the wavelengths of 407, 650, 1310, and 1550 nm, respectively. This research shows that graphene can be used as an efficient platform for broadband photodetectors and provides a strategy for uncooled, high-gain, and low-power photodetectors in telecommunication wavelengths.