Exceptionally Low‐Noise Room‐Temperature Shortwave Infrared Photodetector Based on Low‐Frequency Charge Transfer Transition

Abstract

Current commercial shortwave infrared (SWIR) photodetectors typically necessitate deep cooling to mitigate random fluctuations induced by carrier thermal excitation. Developing high‐sensitivity SWIR photodetectors operating at room temperature is imperative for reducing equipment size and operational expenses. Leveraging the channel depletion mechanism of 2D semiconductors holds promise in suppressing dark current. Another concern lies in the limited choice of infrared absorbing materials and the difficulty in flexibly adjusting the response wavelength region. Here, a high‐sensitive exceptionally low‐noise SWIR photodetector operated is reported at room temperature based on few‐layer WSe2/TCNQ molecules charge transfer complex. Experiments and Calculations results exhibit the low‐frequency (0.6 eV) SWIR absorption stems from the intermolecular charge transfer transition at the interface of heterojunctions. The hybrid photodetector can achieve response efficiently from visible to SWIR (0.6–1.6 µm) with a decent gain 7.7 × 104 and an ultralow dark current noise spectral density (Sn) 1.95 × 10−16 A/Hz0.5 under a channel deplete state at room temperature. The peak specific detectivity is 2.5 × 1013 Jones at 0.7 µm and 7.4 × 1012 Jones at 1.2 µm, (Vgs = 80 V). This work has opened up a new pathway for the development of high‐sensitivity SWIR photodetectors at room temperature.