Phase-Controlled Tin Selenide Photodetectors for Visible Blind to Near-Infrared Optical Radiation

Layered tin selenides have gained tremendous interest due to their distinct tunable semiconducting properties, narrow band gap, low cost, and feasibility for large-scale production. However, the phase controllability of SnSe and SnSe2 is a major challenge for device applications, which should be addressed to ensure repeatability of crystallographic phase, morphology, defects, etc. We have synthesized highly crystalline and phase-controlled (mono, di, mix) tin selenide films using a low-pressure chemical vapor deposition technique by coupling the precursor and substrate temperatures. The optoelectronic behavior of the constructed metal–semiconductor–metal (MSM) tin selenide-based devices responds to the wide spectral range from visible blind (UVB) to near-infrared (NIR). The designed SnSe2-based photodetector has a high optical response to visible light (532 nm) with responsivity, noise equivalent power, and external quantum efficiency of 1260 mA W–1, 8.27 × 10–12 W Hz–1/2, and 295%, respectively. However, the SnSe-based photodetector exhibits a high response for infrared wavelength (1064 nm) with responsivity, external quantum efficiency, and noise equivalent power of 3320 mA W–1, 388%, and 2.88 × 10–12 W Hz–1/2, respectively. The SnSe-based photodetector outperforms the SnSe2 and SnSemix (mixed phase)-based devices in the optical wavelength range from UVB to NIR. A thorough analysis of a phase-controlled tin selenide photodetector with broad optical detecting capability indicates its adaptability to various industrial and technological domains.