Black phosphorus mid infrared photodetector with circular Au/Pd antennas

Black phosphorus has been considered as oneof the most capable two-dimensional materials for use inoptoelectronic nanodevices due to its intrinsic layerednature structure, high mobility of carrier, and tunablebandgap. But its low light absorption prevents its use inhigh-efficiency photodetectors. In this study, the circularAu/Pd antenna-assisted black phosphorus mid-infraredphotodetector which significantly improves the detectionperformance in comparison with BP photodetectorswithout antenna has been proposed. By integrating acircular Au/Pd antenna on the BP surface, the light-BPinteraction was significantly increased. The simulationresults demonstrate that metallic antenna structuresimprove both light absorption and photocarrier collectionin BP phosphorus detectors. The numerical result showsthat the photocurrent of the mid-infrared antenna-assistedBP detector was 5 times larger than that of BPphotodetector without antennas.