GaN Nanowire/Nb-Doped MoS2 Nanoflake Heterostructures for Fast UV–Visible Photodetectors

Abstract

One-dimensional (1D) gallium nitride (GaN) has been used as building blocks to construct optoelectronic nanodevices because of its properties. However, the slow respond speed and narrow spectral detection range of nano-based devices hardly meet the requirements of high-speed and multifunction component development. Herein, we propose a promising strategy to realize photodetectors (PDs) featuring high responsivity, fast response speed, and a wide spectral response range by constructing GaN nanowire/Nb-doped MoS2 flake hybrid heterostructures. Thanks to the synergistic effect of GaN and doped MoS2, the integrated device exhibits high responsivity for ultraviolet (365 nm) as well as visible (500 nm) light, and the maximum value is 1.7 × 102 and 0.34 A/W. For UV detection, the integrated device shows fast response and its rise/fall time is <8/10 ms, which can rival or surpass many 1D nano-based PDs. Further investigation confirms that the type-II band alignment of the GaN/doped MoS2 heterojunction with a conduction band offset and a valence band offset of 0.19 and 2.09 eV, respectively, contributes to the enhanced photogenerated carrier separation and transfer process. The assembled PDs with broad-spectrum photoresponse and fast response speed have great promise as the next-generation hybrid photodetection devices.