Sulfurization engineering of single-zone CVD vertical and horizontal MoS2 on p-GaN heterostructures for self-powered UV photodetectors

Nur 'Adnin Akmar Zulkifli; Nor Hilmi Zahir; Atiena Husna Abdullah Ripain; Suhana Mohd Said; Rozalina Zakaria

doi:10.1039/d2na00756h

Sulfurization engineering of single-zone CVD vertical and horizontal MoS₂ on p-GaN heterostructures for self-powered UV photodetectors

Nanoscale Adv. 2023 Jan 10;5(3):879-892. doi: 10.1039/d2na00756h. eCollection 2023 Jan 31.

Authors

Nur 'Adnin Akmar Zulkifli¹, Nor Hilmi Zahir², Atiena Husna Abdullah Ripain¹, Suhana Mohd Said³, Rozalina Zakaria¹

Affiliations

¹ Photonic Research Centre, University Malaya 50603 Kuala Lumpur Malaysia rozalina@um.edu.my.
² Low Dimensional Material Research Center (LDMRC), Physics Dept. Faculty of Science, University Malaya 50603 Kuala Lumpur Malaysia.
³ Department of Electrical Engineering, Faculty of Engineering, University of Malaya 50603 Kuala Lumpur Malaysia.

Abstract

Molybdenum disulfide (MoS₂) has been attracting considerable attention due to its excellent electrical and optical properties. We successfully grew high-quality, large-area and uniform few-layer (FL)-MoS₂ on p-doped gallium nitride (p-GaN) using a simplified sulfurization technique by the single-zone CVD of a Mo seed layer via E-beam evaporation. Tuning the sulfurization parameters, namely temperature and duration, has been discovered to be an effective strategy for improving MoS₂ orientation (horizontally aligned and vertically aligned) and quality, which affects photodetector (PD) performance. The increase in the sulfurization temperature to 850 °C results in improved structural quality and crystallite size. However, a prolonged sulfurization duration of 60 minutes caused the degradation of the film quality. The close lattice match between p-GaN and MoS₂ contributes to the excellent quality growth of deposited MoS₂. Following this, an n-MoS₂/p-GaN heterostructure PD was successfully built by a MoS₂ position-selectivity method. We report a highly sensitive and self-powered GaN/MoS₂ p-n heterojunction PD with a relatively high responsivity of 14.3 A W^-1, a high specific detectivity of 1.12 × 10¹³ Jones, and a fast response speed of 8.3/13.4 μs (20 kHz) under a UV light of 355 nm at zero-bias voltage. Our PD exhibits superior performance to that of the previously reported MoS₂/GaN p-n PD. Our findings suggest a more efficient and straightforward approach to building high-performance self-powered UV PDs.