High Gain and Broadband Absorption Graphene Photodetector Decorated with Bi₂Te₃ Nanowires

A graphene photodetector decorated with Bi₂Te₃ nanowires (NWs) with a high gain of up to 3 × 10⁴ and wide bandwidth window (400-2200 nm) has been demonstrated. The photoconductive gain was improved by two orders of magnitude compared to the gain of a photodetector using a graphene/Bi₂Te₃ nanoplate junction. Additionally, the position of photocurrent generation was investigated at the graphene/Bi₂Te₃ NWs junction. Eventually, with low bandgap Bi₂Te₃ NWs and a graphene junction, the photoresponsivity improved by 200% at 2200 nm (~0.09 mA/W).