银纳米粒子修饰三维碳纳米管阵列SERS实验

为了使表面增强拉曼散射(SERS)基底的三维聚焦体积内包含更多的“热点”，能吸附更多探针分子和金属纳米颗粒，以便获得更强的拉曼光谱信号，提出了银纳米粒子修饰垂直排列的碳纳米管阵列三维复合结构作为SERS基底，并对其进行了实验研究。利用化学气相沉积(CVD)方法制备了垂直排列的碳纳米管阵列;采用磁控溅射镀膜方法先在碳纳米管阵列上形成一层银膜，再通过设置不同的高温退火温度，使不同粒径的银纳米粒子沉积在垂直有序排列碳纳米管阵列的表面和外壁。SEM结果表明：在有序碳纳米管阵列的表面和外壁都均匀地负载了大量银纳米粒子，并且银纳米颗粒的粒径、形貌及颗粒间的间距随退火温度的不同而不同。采用罗丹明6G(R6G)分子作为探针分子，拉曼实验结果表明：R6G浓度越高，拉曼强度越强，但是R6G浓度的增加与拉曼强度增强并不呈线性变化;退火温度为450 ℃，银纳米颗粒平均粒径在100～120 nm左右，退火温度为400 ℃，银纳米颗粒平均粒径在70 nm左右，退火温度为450 ℃的拉曼信号强度优于退火温度400和350 ℃。

Three-Dimensional Vertically Aligned CNTs Coated by Ag Nanoparticles for Surface-Enhanced Raman Scattering

In order to make surface-enhanced Raman scattering (SERS) substrates contained more “hot spots” in a three-dimensional (3D) focal volume, and can be adsorbed more probe molecules and metal nanoparticles, to obtain stronger Raman spectral signal, a new structure based on vertically aligned carbon nanotubes (CNTs) coated by Ag nanoparticles for surface Raman enhancement is presented. The vertically aligned CNTs are synthesized by chemical vapor deposition (CVD). A silver film is first deposited on the vertically aligned CNTs by magnetron sputtering. The samples are then annealed at different temperature to cause the different size silver nanoparticles to coat on the surface and sidewalls of vertically aligned CNTs. The result of scanning electron microscopy(SEM) shows that Ag nanoparticles are attached onto the sidewalls and tips of the vertically aligned CNTs, as the annealing temperature is different , pitch size, morphology and space between the silver nanoparticles is vary. Rhodamine 6G is served as the probe analyte. Raman spectrum measurement indicates that: the higher the concentration of R6G，the stronger the Raman intensity, but R6G concentration increase with the enhanced Raman intensity varies nonlinearly; when annealing temperature is 450 ℃, the average size of silver nanoparticles is about 100 to 120 nm, while annealing temperature is 400 ℃, the average size is about 70 nm, and the Raman intensity of 450 ℃ is superior to the annealing temperature that of 400 ℃ and 350 ℃.