Whitney Alyson V, Elam Jeffrey W, Zou Shengli, Zinovev Alex V, Stair Peter C, Schatz George C, Van Duyne Richard P
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA.
J Phys Chem B. 2005 Nov 3;109(43):20522-8. doi: 10.1021/jp0540656.
Atomic layer deposition (ALD) is used to deposit 1-600 monolayers of Al(2)O(3) on Ag nanotriangles fabricated by nanosphere lithography (NSL). Each monolayer of Al(2)O(3) has a thickness of 1.1 A. It is demonstrated that the localized surface plasmon resonance (LSPR) nanosensor can detect Al(2)O(3) film growth with atomic spatial resolution normal to the nanoparticle surface. This is approximately 10 times greater spatial resolution than that in our previous long-range distance-dependence study using multilayer self-assembled monolayer shells. The use of ALD enables the study of both the long- and short-range distance dependence of the LSPR nanosensor in a single unified experiment. Ag nanoparticles with fixed in-plane widths and decreasing heights yield larger sensing distances. X-ray photoelectron spectroscopy, variable angle spectroscopic ellipsometry, and quartz crystal microbalance measurements are used to study the growth mechanism. It is proposed that the growth of Al(2)O(3) is initiated by the decomposition of trimethylaluminum on Ag. Semiquantitative theoretical calculations were compared with the experimental results and yield excellent agreement.
原子层沉积（ALD）用于在通过纳米球光刻（NSL）制备的银纳米三角形上沉积1至600个单层的Al₂O₃。Al₂O₃的每个单层厚度为1.1埃。结果表明，局域表面等离子体共振（LSPR）纳米传感器能够以垂直于纳米颗粒表面的原子空间分辨率检测Al₂O₃薄膜的生长。这一空间分辨率比我们之前使用多层自组装单分子层壳进行的远程距离依赖性研究中的分辨率高约10倍。ALD的使用使得能够在单个统一实验中研究LSPR纳米传感器的长程和短程距离依赖性。具有固定平面内宽度和逐渐减小高度的银纳米颗粒产生更大的传感距离。使用X射线光电子能谱、可变角度光谱椭偏仪和石英晶体微天平测量来研究生长机制。研究表明，Al₂O₃的生长是由三甲基铝在银上的分解引发的。将半定量理论计算与实验结果进行了比较，结果吻合良好。
