Active pixel image sensor array for dual vision using large-area bilayer WS2

Abstract

Transition metal dichalcogenides (TMDs) are a promising candidate for developing advanced sensors, particularly for day and night vision systems in vehicles, drones, and security surveillance. While traditional systems rely on separate sensors for different lighting conditions, TMDs can absorb light across a broad-spectrum range. In this study, a dual vision active pixel image sensor array based on bilayer WS₂ phototransistors was implemented. The bilayer WS₂ film was synthesized using a combined process of radio-frequency sputtering and chemical vapor deposition. The WS₂-based thin-film transistors (TFTs) exhibit high average mobility, excellent I_on/I_off, and uniform electrical properties. The optoelectronic properties of the TFTs array exhibited consistent behavior and can detect visible to near-infrared light with the highest responsivity of 1821 A W⁻¹ (at a wavelength of 405 nm) owing to the photogating effect. Finally, red, green, blue, and near-infrared image sensing capabilities of active pixel image sensor array utilizing light stencil projection were demonstrated. The proposed image sensor array utilizing WS₂ phototransistors has the potential to revolutionize the field of vision sensing, which could lead to a range of new opportunities in various applications, including night vision, pedestrian detection, various surveillance, and security systems.