MoSe₂/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 MoSe2 thin films on GaN by magnetron sputtering technique. Raman spectroscopy and high-resolution x-ray diffraction studies disclosed the formation of 2H-MoSe2 whereas x-ray photoelectron spectroscopy confirmed the composition of MoSe2 thin films grown on p-type GaN/sapphire (0001) substrate. The worm-type granular MoSe2 thin film was grown on the GaN surface. The metal-semiconductor-metal-based photodetectors (PDs) were fabricated on MoSe2/p-GaN heterojunction using gold electrodes with a spacing of 20 mu m. Fabricated device shows a high photoresponsivity of similar to 5.12 A/W and detectivity of similar to 3.7 x 10(8) Jones in the ultra-violet (355 nm) region, and a photoresponsivity of similar to 1.5 A/W with a detectivity of similar to 2.23 x 10(8) Jones in the near-infra-red (1064 nm) region at 5 V. Our results demonstrate that large area sputtered MoSe2/ p-GaN PDs devices are beneficial for enhancing photodetector performance.