A surface-enhanced Raman spectroscopy substrate device, including a base substrate, a single or multiple layered nanostructure that contains metals, and a plasma coating. The nanostructure metal is selected from the group including silver, gold, platinum, copper, titanium, chromium, and combinations thereof. The plasma coating has a thickness of 1-200 nm and may locate on the nanostructure layer or on the base substrate. The plasma coating can precisely control the surface characteristics, including surface energy, hydrophilicity, and contact angle, of the SERS device and may then help to regulate the SERS substrate with well defined and uniform water/oil contact angle with small standard deviation. The water contact angle of the SERS substrate may range from 20 to 140 degrees.