Chemically stable and biocompatible SnS2 nanostructures are excellent building blocks for semiconductor-based SERS applications. A comparative UV-SERS study of adsorbed crystal violet (CV) probe molecules on 2D-layered tin disulfide (SnS2) nanoplates and carbon-doped SnS2 nanoflowers is reported. The carbon doping in the SnS2 nanostructure plays a significant role in exciting electrons by UV laser and interfacial charge transfer (CT) process through a substantial reduction in the band-gap. The optimized carbon-doped SnS2 material acts as an excellent SERS substrate, exhibiting significant SERS activity with an enhancement of 2.9 × 102 and a low detection limit of 10−7 mol/L for CV molecules under UV excitation. This remarkable sensitivity and enhancement are attributed to surface defects caused by carbon doping. Energy band engineering on the above 2D semiconductor substrate is a new approach in the SERS field. It may pave the way for the development of novel SERS technology under UV excitation.