Layered selenophosphate HgPSe3 single crystals: a new candidate for X-ray to visible light photodetectors

Abstract

Light detection over a broad spectral range is essential for optoelectronic applications, including spectroscopy, communication sensing and industrial inspection. Even though a few materials can successfully achieve broadband photodetectors, wavelength regimes detected by these detectors are limited to the ultraviolet (UV) to infrared (IR) wavelength range. Furthermore, detection under X-rays remains extensively unexplored because of the lack of desirable materials. Herein, we pioneer a broadband photodetector based on a frontier layered HgPSe₃ single crystal synthesized via chemical vapor transport, as its photodetection covers the X-ray to visible range. This high-quality single crystal is directly used for photodetectors with a facile architecture and achieves a high sensitivity (∼89 μC Gy⁻¹ cm⁻²) under X-rays, which is about 4.5-fold that of a traditional α-Se-based X-ray detector. In the visible light range, the as-fabricated HgPSe₃ crystal-based detector can achieve better eminent optoelectronic performance: a responsivity of 4 A W⁻¹ at ∼650 nm, a detectivity of 1.45 × 10⁹ Jones and a relatively fast photoresponse time (0.49 s rise time under X-rays and 0.08 s rise time under ∼650 nm). These results suggest the potential of the emerging layered thio- and selenophosphate materials for advanced optoelectronic applications.