Growth, Raman Scattering Investigation and Photodetector Properties of 2D SnP

As an important metal phosphides material, 2D tin phosphides (SnP_x 0 <  x ≤ 3) have been theoretically predicted to have intriguing physicochemical properties and potential applications in electronics, optoelectronics, and energy fields. However, the synthesis of high-quality 2D SnP single crystal has not been reported due to the lack of efficiency and reliable growth method. Here, a facile atmospheric pressure chemical vapor deposition (APCVD) method is developed to realize the growth of high-quality 2D SnP nanosheets, by employing tin (Sn) foil as both liquid metal substrates and reaction precursor. Temperature-dependent and angle-resolved polarization Raman spectra observed Raman peaks located at 142.6, 303.3, and 444.2 cm^-1 are concluded to belong to A_1g mode, which are consistent with the theoretical calculation results. Moreover, the field-effect transistor (FET) devices based on SnP nanosheets show a typical n-type characteristic with an on/off ratio of 10³ at 200 K. SnP nanosheets also demonstrate excellent photoresponse performance under the illumination of 473, 532, and 639 nm lasers, which can be tuned by V_gs , V_ds , and light power density. It is believed that these findings can provide the first-hand experimental information for the future study of 2D SnP nanosheets.