High voltage response of graphene/4H-SiC UV photodetector with low level detection

• Published in: Journal of alloys and compounds 2023-12, Vol.969, p.172288, Article 172288
• Main Authors: Jehad, Ala K., Unverdi, Ozhan, Celebi, Cem
• Format: Article
• Language: English
• Subjects: CVD-Graphene; Epitaxial 4 H-SiC; Response speed; Spectral voltage responsivity; UV Photodetector
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2023.172288

A self-powered graphene/silicon carbide (G/4H-SiC) ultraviolet photodetector of a p-i-n like-structure with high voltage response has been fabricated to detect and measure low intensity ultraviolet (UV) radiation. Bilayer graphene sheet grown by chemical vapor deposition (CVD) method was transferred on the top of an epilayer structure of n-/n+ 4 H-SiC. In this structure, two Schottky contacts were formed: one at G/ n- 4H-SiC interface and the other at bulk-4 H-SiC/Cr/Au interface. The photodetector's characteristic measurements revealed low dark current of ∼ 0.58 nA and spectral voltage responsivity of ∼ 0.75 V/W at 300 nm wavelength. Under low level UV illumination of 300 nm wavelength, the photodetector exhibited a leakage current and a photogenerated response voltage of 1.1 nA and 10 mV, respectively. The time-dependent photovoltage measurements displayed a rapid photovoltage response with rise and decay times of ∼74 ns and ∼ 580 ns, respectively. This novel device holds promise for applications requiring sensitive and self-powered UV detection. •A self-powered, p-i-n like-structure UV photodetector with Schottky barriers has been fabricated.•Bilayer CVD graphene was transferred onto an epilayer of n-/n+-4H-SiC junction.•The photodetector shows a high voltage spectral responsivity of ∼ 0.75 V/W at 300 nm wavelength.•The strong built-in potential at epilayer caused in a quick and efficient charge separation.•Due to the thermionic field emission, some charge carriers escape and contribute as a leakage current.