3D arrays of SERS substrate for ultrasensitive molecular detection

Abstract

Systematically arranged arrays of nanostructures were realized using CMOS compatible silicon technologies. The ordered arrays of nanostructures were formed using DUV photolithography, reactive ion etching and physical vapour deposition of silver. By varying the lithography dosage, arrays having different distance of closest approach between adjacent nanostructures are created. The nanostructures also have sharp edges to bring about a further enhancement to the local electromagnetic field. In comparison with other methods of preparing SERS substrate, our method provides advantages of high uniformity and high sample throughput. The Raman spectrum of Rhodamine 6G (R6G) molecules is characterized on our substrates. The substrates with the smaller distance between adjacent nanostructures show the greater enhancement. R6G with concentration up to 1 μM was detected using SERS substrates fabricated.