405 nm ultraviolet photodetector based on tungsten disulphide thin film grown by drop casting method. Issue 18 (24th October 2019)

• Record Type: Journal Article
• Authors: Ahmad, Harith; Rashid, Haroon
• Is Part Of: Journal of modern optics. Volume 66:Issue 18(2019)
• Page Start: 1836
• Page End: 1840
• Publication Date: 2019-10-24
• Subjects: WS2 -- photodetector -- UV -- responsivity -- fall time -- drop-casting; Optics -- Periodicals; 535
• DOI: 10.1080/09500340.2019.1682207
• Languages: English
• ISSNs: 0950-0340

Abstract

ABSTRACT: In this work, a tungsten disulphide or WS2 based heterojunction photodetector device is fabricated on top of Si substrate by simple drop casting. Raman shifts are observed at 350.16 and 419.36 cm −1, confirming the successful growth of the WS2 and the non-stoichiometric WS2 layers which are verified by energy-dispersive X-ray (EDX) spectroscopy. The device is characterized for its optoelectronic properties in the ultraviolet (UV) range of 405 nm. Current–voltage ( I–V ) measurement is performed to obtain the I–V curves of the photodiode under laser illumination at 30.219, 56.335, 80.457, 106.998 and 129.28 mW.cm −2 . The photocurrent is found to be highly dependent on the laser power. The fabricated device has a high responsivity of 145.52 mA/W and a high detectivity of 1.248 × 10 11 Jones for an incident laser power density of 129.28 mW.cm −2 . These observed results are promising and indicate the viability of the proposed design for optoelectronic applications.