Raman enhancement is related to the characteristics of the nanoscale metallic substrates, such as the material, surface morphology, size, and aggregated state of the nanoparticles [19].
Since EM is the main contributor, the nanoscale characteristics of metallic substrates such as composition, particle size, shape, interparticle gap, fissures, and geometry play important roles in the enhancement of SERS [1, 3, 7].
The new substrate (porous LTO) participates in capacity, with no change in volume, and overcomes drawbacks of using metallic substrates such as high cost, fragile structure and the low volumetric specific capacity.
Samarium-based films have been shown to form from aqueous solutions on the surfaces of metallic substrates such as steel or aluminum, and their presence has been reported to decrease substantially the corresponding corrosion rate of the underlying metallic substrate.
Despite the ideally ordered patterns obtained, this method is limited by the pattern transfer protocol, and pattern transferred by imprint lithography directly onto metallic substrates such as Al foils or Al films requires 50-2000 times higher pressures in comparison with imprint lithography on polymer layers [11].
Hydroxylapatite is generally used as a coating material on the metallic substrates, such as titanium alloys, stainless steels and CoCrMo alloys to take the advantageous of both excellent biocompatibility of hydroxylapatite and good mechanical properties of the metals at the same time.
Optimization of SERS signal requires tuning of the plasmon resonances of the metallic substrate such that, for a given laser wavelength, there is maximum enhancement of electromagnetic field around nanoholes.
Non-metallic substrates, such as plastics or oxides, need to be activated before electroless metal deposition.
Oxide films have been formed electrochemically at several metallic substrates, including base metals such as a new Al-based microcrystalline alloy (Al-Fe, V, Si) and at polycrystalline Pd electrodes.
Advanced top-down fabrication methods can produce precision-patterned metallic nanostructures on solid substrates such as silicon wafers.
Convention hydrogenation catalysts including Pd, Pt, and Ni and several types of cathode substrates such as metallic mesh/foam and activated carbon material, were tested.
