Carbon Nitride Thin Film‐Sensitized Graphene Field‐Effect Transistor: A Visible‐Blind Ultraviolet Photodetector

Abstract

Ultraviolet (UV) photodetectors often suffer from the lack of spectral selectivity due to strong interference from visible light. In this study, the exceptional electrical properties of graphene and the unique optical properties of carbon nitride thin films (CNTFs) are used to design visible‐blind UV photodetectors. First, polycrystalline CNTFs with different thicknesses (12–94 nm) are produced by thermal vapor condensation. Compared to the bulk carbon nitride powder, these films have a considerable sp2 nitrogen deficiency, which is thickness dependent. In addition to showing a wider bandgap than the bulk counterpart, their optical absorption profile (in the ultraviolet–visible range) is unique. Critically, the absorbance falls sharply above 400 nm, making the CNTFs suitable for ultraviolet photodetection. As a result, graphene field‐effect transistors (GFETs) sensitized with CNTFs show 103 A W−1 responsivity to UV radiation, a stark contrast to the negligible value obtained in the visible spectrum. The effect of film thickness on the photoresponse is determined, with the thinner CNTF leading to much better device performance. The CNTF/GFET photodetectors are also characterized by their fast response and recovery times, 0.5 and 2.0 s, respectively. These findings pave a simple route for the development of sensitive, visible‐blind UV photodetectors.

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“…1h). 37,38 X-ray maps and the highresolution image show uniform distribution of C, N and P elements and the micro-sheet structure of the Pi-Ho@C 3-x N 4 (Fig. 1i).…”

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“…Palanisamy et al transferred g-C 3 N 4 thin film onto the surface of single-layer graphene field-effect transistor (FET) as the UV photodetector. 84 The light response is dependent on the g-C 3 N 4 thin film, achieving an on/off ratio of 157 and responsivity was up to 3 × 10 3 A W −1 . Shan et al investigated the photodetection characteristics of g-C 3 N 4 through in situ pressure-dependent electrical test.…”

Enhance Carrier Diffusion of Monolayer MoSe2 by Interface Engineering

“…Transistors, serving as the fundamental building blocks of CMOS (complementary metal–oxide–semiconductor), have gained widespread utilization in integrated circuits. , Field effect transistors (FETs) are an important part of integrated circuits and play an important role in information science and technology. , Two-dimensional (2D) materials possess atomically thin thicknesses and no dangling bonds on their surfaces, which endows them with gate controllability and avoid unwanted scattering. , Therefore, 2D materials have attracted great interest from researchers. − 2D FETs have been used in a variety of emerging technologies such as biomimetic devices, optoelectronic devices, sensors, valleytronics, and neuromorphic computing. − Transition metal dichalcogenides (TMDs) have received significant attention due to their unique layered material structure and physical properties. In particular, monolayer (ML) MoSe 2 , a semiconductor material with wide bandgap and better light absorption, is highly suitable as a channel material for FETs.…”