We created novel SERS substrates by metalizing (Ag or Au) Si nanograss fabricated by a Bosch process on single
crystalline silicon. We demonstrated that the fabricated SERS substrates are highly sensitive. The sensitivity of the
substrates depends on the target molecules, the excitation laser wavelengths and the metal coating on the silicon
nanograss. With the optimal excitation condition at 633 nm, an enhancement factor of 6 × 10<sup>7</sup> can be achieved for trans-
1,2-bis(4-pyridyl)-ethylene (BPE) molecules on the gold coated silicon nanograss substrate.