Temperature-Dependent Raman Responses of the Vapor-Deposited Tin Selenide Ultrathin Flakes

Tin selenide (SnSe) is a newly emerging layered material. SnSe with low dimensionality has been reported as an appealing material with a diverse range of applications such as rechargeable lithium-ion batteries, memory switching devices, solar energy conversion, thermoelectric energy conversion, and near-infrared optoelectronic devices. Here we synthesized SnSe ultrathin flakes on SiO2/Si substrates through simple vapor deposition route and investigated its temperature-dependent Raman spectroscopy behavior with 532, 633, and 785 nm excitation wavelengths. It was found that the A(g)(2), A(g)(3) and B(3)g modes soften as temperature increases from 98 to 298 K under all wavelengths. Our results revealed anharmonic phonon properties of SnSe, and they will benefit the advanced study of its thermal properties. This approach will also have large application in characterizing the optical, electronic, and thermal properties of other novel layered materials. Moreover, our results can be utilized to measure the temperature of SnSe-based nanodevices without destruction.