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CVD graphene/SiC UV photodetector with enhanced spectral responsivity and response speed.

Authors :
Jehad, Ala K.
Fidan, Mehmet
Ünverdi, Özhan
Çelebi, Cem
Source :
Sensors & Actuators A: Physical. Jun2023, Vol. 355, pN.PAG-N.PAG. 1p.
Publication Year :
2023

Abstract

A self-powered, high-performance graphene/Silicon Carbide (G/4H-SiC) ultraviolet Schottky junction photodetector has been fabricated, and the effect of using monolayer and bilayer graphene on the device performance parameters was investigated. P-type graphene sheets were grown by the chemical vapor deposition (CVD) method, while 4H-SiC material consists of an epilayer structure of n-/n+ on bulk n-SiC. Two photodetector devices have been studied, one with monolayer graphene (MLG) and the other with bilayer graphene (BLG). The proposed photodetector structure reveals the highest spectral responsivity known of a G/4H-SiC UV photodetector so far. Electronic and optoelectronic characterizations were done under an ultraviolet wavelength range from 240 to 350 nm. The results show two spectral responsivity maxima (R max) at 285 nm and 300 nm wavelengths. Exhibiting two maxima in spectral responsivity and detectivity is caused by the constructive and destructive interference effects of multiple reflections at the SiC epilayer's interfaces. The photodetector devices exhibit high spectral responsivity (R ∼ 0.09 AW−1), maximum detectivity (D* ∼ 2.9 × 1012 Jones), and minimum noise equivalent power (NEP ∼ 0.17 pWHz-1/2) in both devices. Using bilayer graphene instead of monolayer showed no significant change in both the photogenerated current and the spectral responsivity due to the higher absorption coefficient of bilayer graphene, however, it exhibited a significant improvement in the response speed. The response speed was found to increase by 50 % when bilayer graphene was used as a hole collecting electrode in the G/4H-SiC junction. This is because bilayer graphene creates a narrower depletion layer and higher electric field, which promotes efficient charge separation and recombination. [Display omitted] • A self-powered, high-performance G/4H-SiC ultraviolet Schottky junction photodetector has been fabricated. • The impact of employing monolayer and bilayer CVD graphene on the device performance parameters was investigated. • The proposed photodetector structure reveals the highest spectral responsivity known for G/SiC UV photodetectors. • Two spectral responsivities were observed at 285 nm and 300 nm due to the constructive and destructive effects. • The photodetector with bilayer graphene provides an efficient charge separation, with a t r = 5.4 μs and t d = 3.2 μs. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09244247
Volume :
355
Database :
Academic Search Index
Journal :
Sensors & Actuators A: Physical
Publication Type :
Academic Journal
Accession number :
162977608
Full Text :
https://doi.org/10.1016/j.sna.2023.114309