A new method to prepare SERS-active substrate is reported.Via electroless metal deposition,gold films with different morphology are deposited onto silicon wafer from HF aqueous solution containing HAuCl4.Surface morphology and structure are analyzed by SEM.The measurements of the SERS spectra of crystal violet on the substrates indicate that the SERS signal intensity is enhanced first and then weakened as the deposition reaction time increases,and SERS effect is markedly superior to the gold colloid system ...