MoSe 2 /p-GaN heterojunction for enhanced UV and NIR photodetector

In recent years, p–n junction devices formed by wide-bandgap semiconductors and layered transition metal dichalcogenides have been promising candidates for applications in broadband photodetection. In this work, we have deposited MoSe 2 thin films on GaN by magnetron sputtering technique. Raman spectroscopy and high-resolution x-ray diffraction studies disclosed the formation of 2H-MoSe 2 whereas x-ray photoelectron spectroscopy confirmed the composition of MoSe 2 thin films grown on p-type GaN/sapphire (0001) substrate. The worm-type granular MoSe 2 thin film was grown on the GaN surface. The metal–semiconductor-metal-based photodetectors (PDs) were fabricated on MoSe 2 /p-GaN heterojunction using gold electrodes with a spacing of 20 µm. Fabricated device shows a high photoresponsivity of ~ 5.12 A/W and detectivity of ~ 3.7 × 10 8 Jones in the ultra-violet (355 nm) region, and a photoresponsivity of ~ 1.5 A/W with a detectivity of ~ 2.23 × 10 8 Jones in the near-infra-red (1064 nm) region at 5 V. Our results demonstrate that large area sputtered MoSe 2 /p-GaN PDs devices are beneficial for enhancing photodetector performance.