The tip-sample water bridge and light emission from scanning tunnelling microscopy.
The tip-sample water bridge and light emission from scanning tunnelling microscopy.
复制标题
扫描隧道显微镜的尖端样品水桥和光发射。
DOI：
10.1088/0957-4484/20/33/335202
复制
发表时间：
2009
期刊：
影响因子：
3.5
通讯作者：
Boyle MG
中科院分区：
文献类型：
--
作者：
Boyle MG
从扫描隧道显微镜（LESTM）的光发射光谱作为相对湿度的函数进行了研究，并显示出提供了一种新的和敏感的手段，用于探测的生长和性质的水弯月面在纳米尺度上。的光发射过程的经验模型制定和成功地复制光强度的衰减和光谱变化观察到的相对湿度增加。该建模表明随着湿度的增加，或更相关地，负责光发射的局部表面等离子体的体积的尖端-样品结的渐进水填充;它还占相对于所施加的偏压的极性的水分子的结构的不对称性的影响。这与尖端样品纳米腔中的非极性液体的情况并列，其中没有观察到光发射的极性依赖性。与通过测量仪器控制的反馈参数对其他扫描探针实验中存在/不存在水桥进行离散检测不同，LESTM提供了一种以亚纳米灵敏度连续监测水桥发展的方法。结果是相关的应用，如蘸笔纳米光刻和电化学扫描探针显微镜。
The light emission spectrum from a scanning tunnelling microscope (LESTM) is investigated as a function of relative humidity and shown to provide a novel and sensitive means for probing the growth and properties of a water meniscus on the nanometre scale. An empirical model of the light emission process is formulated and applied successfully to replicate the decay in light intensity and spectral changes observed with increasing relative humidity. The modelling indicates a progressive water filling of the tip–sample junction with increasing humidity or, more pertinently, of the volume of the localized surface plasmons responsible for light emission; it also accounts for the effect of asymmetry in structuring of the water molecules with respect to the polarity of the applied bias. This is juxtaposed with the case of a non-polar liquid in the tip–sample nanocavity where no polarity dependence of the light emission is observed. In contrast to the discrete detection of the presence/absence of a water bridge in other scanning probe experiments through measurement of the feedback parameter for instrument control, LESTM offers a means of continuously monitoring the development of the water bridge with sub-nanometre sensitivity. The results are relevant to applications such as dip-pen nanolithography and electrochemical scanning probe microscopy.