Abstract
This paper reports on highly-sensitive adenine molecule detection by surface enhanced Raman spectroscopy with single molecule sensitivity using directionally and regularly arrayed gold nanoparticle dimers with the diameter of 100 nm on the substrate. A particle dimer shows huge electromagnetic enhancement when particle connection direction is matched to polarization direction of light. In this study the dimers were arrayed by the nanotrench-guided self-assembly for generating huge total Raman enhancement. The fabricated structures were used for adenine molecule detections of 10-11 M aqueous solutions. We successfully detected the molecules at the ultra-low concentration, which indicates single molecule sensitivity. The concentration limit of detection had previously been 10-8 M in the reported literatures, which used the simple method with the prefabricated SERS substrate. Our developed substrate exhibited 103 times sensitivity. The clear peaks were found at the integration time of 0.1 s. We confirmed that our developed SERS substrate enables us to detect adenine molecules with high sensitivity and short integration time.
