Technologies

Offered here is a new method to cost-effectively batch produce consistent, high-quality, high-yield Tip-enhanced Raman Spectroscopy (TERS) Probes. Using a bath process, SiO ₂ AFM probes are selectively coated with a dense size-ordered-layer of engineered nanoparticles, providing a high resolution & high sensitivity probe tip that exhibits reproducible enhancement from one tip to the next. Unlike current state-of-the-art (evaporative coating, wire-etching or top-down construction) the current tip is both reliable and predictable in its performance. Leveraging this new method for TERS Probe production, the full potential for TERS imaging should be realized at cost effective prices.

The given method improves upon current approaches in several aspects:

1) The process uses superior materials. As opposed to bulk metal wires or deposited metal films, the method herein uses size and shape controllable nanoparticles. These particles are single crystalline, nearly-atomically flat and are advantageous over deposited or etched materials which have shapes that are uncontrollable on the nanoscale, are rough and polycrystalline.

2) Because the fabrication process is independent of the size or shape of the nanoparticles used, this method succeeds in engineering the desired size and shape of nanoparticle for a given probe, allowing precise tuning of the antenna’s performance to meet experimental criteria.

3) The combination of high quality materials and tunability has led to reproducible enhancement factors in the range of 10 ⁸ -10 ⁹ at a wavelength of 785 nm. This compares to most etched metal or evaporation coated tips which are generally in the 10 ⁶ -10 ⁷ range.

4) This is a batch process. Many of the existing fabrication techniques have single-tip throughput. Thus far, this method has demonstrated up to 10 simultaneously fabricated tips, made in 3-5 hours, with a greater than 80% yield. It should be noted that fabricating 50 or 100 tips would add little to no extra time to the process.