  We demonstrate gold coated polymer surface enhanced Raman scattering (SERS)
substrates with a pair of complementary structures--positive and inverted
pyramids array structures fabricated by multiple-step molding and replication
process. The uniform SERS enhancement factors over the entire device surfaces
were measured as 7.2 X 10^4 for positive pyramids substrate while 1.6 X 10^6
for inverted pyramids substrate with Rhodamine 6G as the target analyte. Based
on the optical reflection measurement and FDTD simulation result, the
enhancement factor difference is attributed to plasmon resonance matching and
to SERS "hot spots ". With this simple, fast and versatile complementary
molding process, we can produce polymer SERS substrates with extremely low
cost, high throughput and high repeatability.
