Abstract
Abstract Sensitive solar-blind ultraviolet (UV) photodetectors are important to various military and civilian applications, such as flame sensors, missile interception, biological analysis, and UV radiation monitoring below the ozone hole. In this paper, a solar-blind UV photodetector based on a buried-gate graphene field-effect transistor (GFET) decorated with titanium dioxide (TiO2) nanoparticles (NPs) was demonstrated. Under the illumination of a 325-nm laser (spot size ~2 μm) with a total power of 0.35 μW, a photoresponsivity as high as 118.3 A/W was obtained, at the conditions of zero gate bias and a source-drain bias voltage of 0.2 V. This photoresponsivity is over 600 times higher than that of a recently reported solar-blind UV photodetector based on graphene/vertical Ga2O3 nanowire array heterojunction (0.185 A/W). Experiments showed that the photoresponsivity of the TiO2 NPs decorated GFET photodetectors can be further enhanced by increasing the source-drain bias voltage or properly tuning the gate bias voltage. Furthermore, the photoresponse time of the TiO2 NPs decorated GFET photodetectors can also be tuned by the source-drain bias and gate bias. This study paves a simple and feasible way to fabricate highly sensitive, cost-efficient, and integrable solar-blind UV photodetectors.
Highlights
Ultraviolet (UV) photodetectors are important for many applications such as space communication, flame detection, military surveillance, industrial quality control, and environmental monitoring [1,2,3,4,5,6,7,8,9,10]
A solar-blind UV photodetector based on a buried-gate graphene field-effect transistor (GFET) decorated with titanium dioxide (TiO2) nanoparticles (NPs) was demonstrated
Li et al.: Solar-blind ultraviolet detection based on TiO2 nanoparticles decorated graphene solar-blind, limiting their applications to some military and civilian fields such as missile interception, biological analysis, and UV radiation monitoring below the ozone hole [26]
Summary
Ultraviolet (UV) photodetectors are important for many applications such as space communication, flame detection, military surveillance, industrial quality control, and environmental monitoring [1,2,3,4,5,6,7,8,9,10]. For example by synthesizing a layer of silicon QDs doped with boron on a back-gated graphene field-effect transistor (GFET), a photoresponsivity up to ~108 A/W and a detectivity of ~1012 Jones were obtained at 375 nm [33]. Li et al.: Solar-blind ultraviolet detection based on TiO2 nanoparticles decorated graphene solar-blind, limiting their applications to some military and civilian fields such as missile interception, biological analysis, and UV radiation monitoring below the ozone hole [26]. A simple and feasible technique was demonstrated to realize highly sensitive and solar-blind UV photodetectors, by decorating a buried-gated GFET with solution-synthesized TiO2 NPs. The buried-gate structure allows tunable optical properties via a small gate voltage, while the solution-synthesized TiO2 NPs, which are solar-blind, nontoxic, low-cost and long-term stable [24, 34, 35], significantly increases the photoresponsivity. The photoresponsivity and photoresponse time of the devices can be modulated by applying a small (≤1 V) gate bias or/and changing the source-drain bias voltages, to meet the needs in different application situations
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