Localized surface plasmon enhanced photoresponse of AlGaN MSM solar-blind ultraviolet photodetectors

Abstract

Enhanced spectra photoresponse was realized in Al0.4Ga0.6N metal-semiconductor-metal solar-blind ultraviolet photodetectors (PDs) by using Al nanoparticals (NPs). The fabricated AlGaN solar-blind PDs exhibit high responsivity and low dark current. By forming different diameters of Al NPs on AlGaN surface, the peak responsivity of the devices appears more than two-fold increase compare to the PDs without Al NPs under the bias voltage of 8 V, and the device with 150 nm Al NPs reaches the highest responsivity of 0.30 A W−1. In order to explore the enhancement mechanism of AlGaN solar-blind PDs with Al NPs, the extinction spectra and electric field distribution of Al NPs were calculated using finite-difference time-domain (FDTD) simulation based on the quasi-particle approximation, which demonstrates that the significant enhancement performance is due to the localized surface plasmon (LSP) effect of Al NPs. The approach provided in this work is promising for the fabrication of high performance of AlGaN-based solar-blind ultraviolet PDs.