MoSe2/n‐GaN Heterojunction Induced High Photoconductive Gain for Low‐Noise Broadband Photodetection from Ultraviolet to Near‐Infrared Wavelengths

Heterojunction photodiodes comprising of layered metal chalcogenides and wide‐bandgap semiconductors are a promising candidate for broadband photodetection. In this work, nanolayered Molybdenum diselenide (MoSe2)/Gallium Nitride (GaN) based photodetector has been demonstrated from ultraviolet to near‐infrared range (300–1000 nm). The performance is investigated by conducting Kelvin probe force microscopy to measure the conduction band offset at the interface of the heterojunction. It is used to analyze the energy‐band diagrams to understand the current transport mechanism. The device exhibits a high photoconductive gain of 1.8 × 104, responsivity of 5580 A W−1, detectivity of 1.9 × 1011 Jones and low noise equivalent power of 10 fW Hz−1/2 at 365 nm. Additionally, finite difference time domain simulations are performed for the MoSe2/n‐GaN heterostructure to authenticate the broadband photodetection spectrum. Therefore, the outcomes of this study validate the suitability of MoSe2/n‐GaN heterojunction devices for high responsivity and detectivity applications.