Optical Switching Device Based on a Crystalline SnSe2 Photodetector in Diverse Conditions

Specifically for the optoelectronics field, it is always a provocative task for researchers to fabricate a device that can endure diverse extreme conditions without losing its fundamental properties. Metal dichalcogenides have stimulated influential research inquisitively due to the noteworthy optoelectronic properties and device applications designed for extreme environmental circumstances. Among metal dichalcogenides, SnSe2 is an exceptionally studied material due to its extraordinary photosensing ability. In the present article, exploration of the photoresponse nature of the vapor-phase-grown SnSe2 single crystal is elaborated comprehensively. The stoichiometric purity of constituents was verified by the energy-dispersive X-ray analysis (EDAX). The X-ray diffraction (XRD) pattern unveiled a highly crystalline hexagonal lattice structure. A surface morphological analysis is carried out by optical and scanning electron microscopy (SEM) experiments in which layered growth mechanism and randomly oriented hexagonal sheets are observed. Additionally, crystalline nanoflakes are observed in high-resolution transmission electron microscopy (HR-TEM), wherein the interlayer lattice spacing is found to be 0.65 nm. The first-order temperature coefficient and anharmonicity constant are determined from the dependence of Raman mode on low temperatures. Afterward, the photodetection properties are inspected for distinct conditions such as perpendicular and parallel to the c-axis, varied intensity of mono- and polychromatic illumination with different externally applied biases to the detector, and cryogenic temperatures down to 10 K. To the best of our knowledge, sensor properties at 10 K are being reported for the first time in this article. As per investigation, the remarkable properties of SnSe2 single crystals such as reproducibility, steadiness, self-biased nature, ability to withstand and responding to the illumination even at a low temperature of 10 K make them a strong candidate for future optoelectronic switching applications for cryotronics.