Selectively Al₂O₃ Passivated WSe₂/GaN Heterostructure for Ultralow-Noise High-Speed Broadband Photodetection

Hybrid heterostructures of layered metal chalcogenides and semiconductors offer wide spectrum detection opportunities. This work reports the fabrication of a WSe2/GaN hybrid heterostructure device for broadband light detection from the ultraviolet to near-infrared range (325–950 nm). The current transport mechanism is investigated by temperature-dependent (77–300 K) current–voltage measurements. The strong built-in electric field, low dark current, and barrier height of 0.66 eV significantly enhance the device performance metrics. The device exhibits a maximum responsivity of 1.03 A/W under a low illumination density of 0.35 mW/cm2 at 785 nm. The low-frequency noise measurements reveal its ultralow-noise detection with a minimum noise equivalent power of 3.6 × 10–14 W/Hz1/2. The selective passivation of the device promotes a low dark current and high speed with a rise/fall time of 271 μs/294 μs. Consequently, the outcome of this report presents a promising perspective for hybrid heterostructure-based photodetectors for future generations.