Hybrid Plasmonic Nanorods/VO2 Photodetectors Sensitive to Short‐Wave Infrared Photons with Fast Response

Abstract

Thermal detectors, such as bolometers functioning by detecting the radiation‐induced temperature changes, represent a promising route to achieve infrared detection and imaging. In this context, vanadium dioxide (VO2), a narrow bandgap (Eg) semiconductor (Eg ≈0.6–0.7 eV) with a unique near‐room‐temperature reversible metal‐to‐insulator transition (MIT), has emerged as one of the key materials for uncooled bolometer‐type short‐wave infrared (SWIR) photodetectors. In this work, photodetectors sensitive to the SWIR spectrum are fabricated to function at room‐temperature by coupling solution‐processed tungsten (W6+)‐doped VO2 thin films to colloidal plasmonic gold (Au) nanorods (NRs). Due to the dual beneficial roles of the NRs as both the photothermal heating and plasmonic antenna effects, the hybrid Au NR/VO2 devices exhibit significant advantages in terms of photosensitivity and detection range in comparison to the control devices without plasmonics. Together with the low external DC bias required (0.5 V) and the fast response speed (trise down to 14 ms), the present hybrid plasmonic‐VO2 thin film devices suggest a viable approach toward the development of future cost‐effective SWIR photodetectors.