Ultra-low-power photodetector based on a high-photoresponse, plasmonic-effect-induced gateless quasi-freestanding graphene device
- Applied Surface Science
Large-area metal-graphene-metal UV–Visible photodetectors fabricated on quasifreestanding graphene (QFSG)/vicinal SiC (8° off-axis) wafers are applicable to future low-power consumption systems. They demonstrate effective photoresponse under 365 nm (UV) and 405 nm (Visible) light irradiation upon the application of a built-in electric field (self-biased) and ultra-low bias (−10 mV). Photocurrent gain and responsivity under UV–Visible light are more significant on QFSG/vicinal SiC than on epitaxial graphene (EG)/SiC(0 0 0 1) because of the freestanding nature of the topmost layer, absence of a buffer layer, and primary carrier scattering/trapping centers. Further, they are tuned by localized surface plasmon resonance using gold nanoparticles (AuNPs). In the self-power mode and low-bias mode in QFSG/vicinal SiC, the photocurrent is enhanced by 9-fold and 120-fold, respectively, compared to the photocurrent in EG/SiC(0 0 0 1). The responsivity of QFSG/vicinal SiC after AuNP treatment is ≈1.65 mA/W (at zero bias) and ≈20 mA/W (at −10 mV) under 365 nm light illumination (intensity = 18 mW/cm−2), significantly higher than that of EG/SiC (0 0 0 1). This device shows a similar trend of photoresponse under 405 nm light illumination. These results confirm that this QFSG/vicinal SiC combined with AuNPs possesses potential for application in UV–Visible detection with minimum power consumption.