Temperature-dependent Raman spectroscopy and sensor applications of PtSe(2) nanosheets synthesized by wet chemistry

We report on a wet chemistry method used to grow PtSe(2) nanosheets followed by thermal annealing. The SEM and TEM analysis confirms the formation of PtSe(2) nanosheets. Furthermore, XRD, Raman, XPS and SAED patterns were used to analyze the crystal structure and to confirm the formation of the PtSe(2) phase. The temperature-dependent Raman spectroscopy investigations were carried out on PtSe(2) nanosheets deposited on Si substrates in the temperature range 100–506 K. The shifts in Raman active E(g) and A(1g) modes as a function of temperature were monitored. The temperature coefficient for both modes was calculated and was found to match well with the reported 2D transition metal dichalcogenides. A PtSe(2) nanosheet-based sensor device was tested for its applicability as a humidity sensor and photodetector. The humidity sensor based on PtSe(2) nanosheets showed an excellent recovery time of ≈5 s, indicating the great potential of PtSe(2) for future sensor devices.