| Summary: | 博士 === 國立臺灣大學 === 材料科學與工程學研究所 === 106 === The purpose of this thesis is to investigate the feasibility that the Au-based thin film metallic glasses (TFMGs) could be utilized for plasmonic sensor applications, including localized surface plasmon resonance (LSPR) based sensor and propagating surface plasmon resonance (PSPR) based sensor.
Firstly, we synthesized four compositions of fully amorphous AuCuSi TFMGs by magnetron co-sputtering. The glass transition temperature, which is also the temperature of the critical transition point from elastic/plastic deformation to time-dependent viscous flow, was determined using nanoindentation. The nanoindentation creep tests performed with hemispherical and Berkovich indenter tips at temperature range of 50 oC–170 oC were proven to be suitable for the viscosity measurements of AuCuSi TFMGs. The activation energy of the flow process was also evaluated from the indentation results and good agreement was obtained between the results evaluated from hemispherical and Berkovich tips. Finally, a nano-scaled imprinted AuCuSi.
Secondly, we verified the feasibility that the AuCuSi TFMG could be applied to PSPR based sensor. By using the AuCuSi TFMG, the refractive index change of surrounding environment could be observed by angel resolved reflection spectrum. Compared with traditional used Au thin film in PSPR based sensor, AuCuSi TFMG also exhibit good sensitivity to the analytes and much better adhesion force to the substrates.
Thirdly, thermal plastic forming ability of the as-deposited thin films in their super-cooled liquid regions (SCLR) were utilized to fabricate micron- and nano-scaled patterns as surface enhanced Raman scattering (SERS) substrates. Our study showed that AuCuSi TFMGs process the required dielectric properties for SERS applications. To fabricate periodic arrays for SERS, nano-imprint lithography, a method based on the fluidity of TFMGs in the SCLR, was applied to reduce the cost and complexity of traditional manufacture. Our optical simulation results provided the guidelines for processing of optimum imprinted nano-structures on the Au-based TFMGs. Optical properties, including reflection and scattering, were characterized for SERS substrates and the sensitivity of these substrates were estimated subsequently. Various patterns with the features size from sub-100 nm to micrometer and Raman enhancement factor of crystal violet up to 1.4×105 were achieved.
Finally, the feasibility that the AuCuSi TFMG could be used as the activation layer for the Tip-enhanced Raman microscope (TERS) was verified. However, subject to experimental resources, only optical simulations were accomplished, which gave strong evidence that traditional pure Au films could be replaced by AuCuSi TFMG. As the hardness of AuCuSi was about three times higher than that of pure Au and better adhesion force to the substrates, we predicted that AuCuSi will extend the life-time of the TERS tips and has excellent potential for applications.
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