Noble Metal Thin Film Thickness Optimization for Sharp Surface Plasmon Resonance Reflectance Curve

The production of a high-sensitivity surface Plasmon resonance (SPR) sensor depends on a few main factors, such as metal thin film types and thicknesses, light coupling techniques and acceptable EM wave polarization modes. This work is carried out to investigate the impact on the SPR characteristics of noble metal thicknesses, namely gold and silver, for optical sensor applications. To excite surface Plasmon polaritons (SPP), a Kretschmann prism coupling was used. The thicknesses of noble metal thin films were varied between t=30nm and 60nm. The characteristics of SPR peaks such as Q-factor and FWHM were studied in SPR signal analyses. In comparison with silver, Q-factor results showed an outstanding optical property of gold at t= 40 nm due to its high Q-factor values, which confirms its ability to produce excellent SPP quantities. In conclusion, gold noble metal at t= 40nm is capable of producing optimum SPR. In the development of the highly sensitive SPR sensor, this excellent criterion put gold as a spectacular candidate for optical sensor applications.

Theoretical Verification of Film Forming in Local Electroplating Process with Electrolyte Suction Tool

Electroplating has many applications, including surface hardening and metal thin film manufacturing. In conventional electroplating, the entire workpiece is immersed in the plating solution. Since the whole surface in contact with the solution is plated, a masking operation to remove the unnecessary plating film is required. This is especially applicable to local plating in the case of ornament plating, surface hardening method, among others. However, these additional processes result in substantial increase in processing time and cost. Earlier, we achieved maskless local electroplating with a smooth surface using a suction tool, in which the electrolyte was retrieved by a suction pump through a suction hole. Even so, formation of film on electroplating is yet to be verified by simulations. Herein, we performed experiments and simulations of the local electroplating by varying the processing time before comparing the results. Finally, the validity of the film forming was examined by discussing the results.