Tip-enhanced Raman spectroscopy (TERS) offers one of the best techniques for optical analysis and imaging of samples at nanoscale. The most important point in TERS experiments is to obtain a high signal enhancement through a metallic nanotip.

We present photoreduction as a facile fabrication method for growing near-field tips having only one silver nanoparticle at the tip apex. Our technique that selectively grows a silver nanoparticle at the tip apex involves just a simple laser radiation without any requirement of complicated techniques and experimental systems, and the entire fabrication process can be completed in a very short time (a few minutes). It is very easy to control the size of the fabricated silver nanoparticle to meet the TERS experimental requirements.

These tips grown by our method provide an order of magnitude higher enhancement in comparison with the fully metallized standard tips. Our technique of growing tips with a silver nanoparticle has a possibility of improving TERS to a level where it could be a more practical and powerful nanospectroscopic tool due to the better enhancement of the weak Raman signal.