CdS core-Au/MXene-based photodetectors: Positive deep-UV photoresponse and negative UV–Vis-NIR photoresponse

Exploring photodetectors with higher responsitivity and broader spectral response is crucial for optoelectronic applications. Inverse photoresponse is discovered from photodetectors based on cadmium sulfide modified by Au (CdS core-Au). The devices are capable of detecting photons with a broader spectrum from deep-ultraviolet to near-infrared. Under the illumination of visible light at 405 nm, negative photoresponse with higher responsivity (86 mA/W) and larger specific detectivity (1.34 × 1011 Jones) are observed owing to the thermal mechanism. Upon deep-ultraviolet light illumination, the photodetectors exhibit positive photoresponse. These findings provide a new approach to broad spectral photodetectors and other inventive optoelectronic devices.