This work examines the influence of thickness on the electrical transport properties of mechanically exfoliated two-dimensional ${\mathrm{SnSe}}_2$ nanosheets, derived from the bulk single crystal. Contrary to the conventional trend observed in two-dimensional systems, we find a semiconducting to metallic resistivity behavior with decreasing thickness. The analysis of low-temperature conduction indicates an increased density of states at the Fermi level with decreasing thickness, which is further corroborated by gate bias-dependent conductance measurement. The enhanced conductivity in thinner flake is attributed to the $n$-type doping arising from surface defect states. The presence and evolution of these defect states with thickness are probed by thickness-dependent room-temperature Raman spectroscopy. Our study provides insights into the thickness-dependent electronic transport mechanism of ${\mathrm{SnSe}}_2$ and the crucial role of defect states in governing the observed conductivity behavior.

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• Transport phenomena
• 2-dimensional systems
• Transition metal dichalcogenides
• Raman spectroscopy
• Resistivity measurements