C60 Functionalized Single-Walled Carbon Nanotube-based Phototransistor for Efficient Detection of Visible Light Under Appropriate Gate Electrostatics

Abstract

The current study concerns highly reliable visible light sensing by C60 fullerene functionalized single-walled carbon nanotube (SWCNT) based phototransistor. The absorbance of visible light (532 nm) increases significantly due to the formation of an interlink between the SWCNT network and C60 clusters. Photogenerated excess electrons in SWCNT are trapped by the C60 clusters and increase the effective hole concentrations in the SWCNT channel, which eventually improves the photoconductive gain. C60-SWCNT channel is further integrated into the back gated field effect transistor (FET) structure in which 90 nm SiO2 dielectric thickness is used. The responsivity toward visible light is further enlarged with appropriate negative gate electrostatic. In order to ensure the morphological and structural behavior of C60-SWCNT, various microscopic and spectroscopic characterizations are performed. The C60-SWCNT phototransistor exhibits responsivity of 1.219 A W−1 at Vgs = – 21 V. The detectivity and rise/fall time of C60-SWCNT came around to be 2.34 × 1010 Jones, 86.42 ms/3.35 ms at the same Vgs. The maximum external quantum efficiency (EQE) of the C60-SWCNT phototransistor is very high, ≈274%. In the overall study, a comprehensive discussion is introduced on the effect of variable gate potential on the performance of the C60-SWCNT phototransistor.