Fig. 1. (a) SEM image of gold nano-cube; (b) absorption spectrum of gold nano-cube.(a)金纳米立方体的SEM图; (b)金纳米立方体的吸收谱

Fig. 2. SERS spectra of R6G molecules on the glass substrate in the conditions of the mixed aqueous solution of gold nano-cubes with different concentrations and R6G with the concentration of 10⁻⁴ mol/L. 10⁻⁴ mol/L的R6G、不同浓度金纳米立方体混合水溶液条件下玻璃基片上的SERS光谱

Fig. 3. (a) Relationship between maximum electric field enhancement factor and the thickness of PMMA in composite structure; (b) electric field distribution of composite structure with a 15-nm-thick PMMA spacer.(a)复合结构中最大电场增强因子与PMMA厚度的关系; (b) 15 nm PMMA厚度下复合结构中的电场分布

Fig. 4. SERS spectra of R6G molecules on the composite structure in the conditions of the mixed aqueous solution of gold nano-cubes with different concentrations and R6G with the concentration of 10⁻⁴ mol/L. 10⁻⁴ mol/L的R6G、不同浓度金纳米立方体混合水溶液条件下复合结构中的SERS光谱

Fig. 5. SERS spectra of R6G molecules on the glass substrate and composite structure in the condition of the mixed aqueous solution of gold nano-cubes with the concentration of 5.625 and R6G with the concentration of 10⁻⁴ mol/L. 10⁻⁴ mol/L的R6G, 5.625 的金纳米立方体混合水溶液条件下玻璃基片和复合结构的SERS光谱

Fig. 6. SERS spectra of R6G molecules on the composite structure in the conditions of the mixed aqueous solution of gold nano-cubes with the concentration of 5.625 (a) R6G with different concentrations of 10^–6, 10⁻⁸, 10⁻¹⁰, 10^–11 mol/L; (b) R6G with the concentration of 10⁻¹¹ mol/L. 5.625 的金纳米立方体混合水溶液条件下, 复合结构的SERS光谱　(a)不同R6G浓度; (b) 10⁻¹¹ mol/L的R6G浓度(1 M = 1 mol/L)