Nanoscale Physics, Chemistry and Engineering Research Laboratory, School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
Nanotechnology. 2017 Mar 10;28(10):105711. doi: 10.1088/1361-6528/aa5938. Epub 2017 Jan 13.
A compact proximal retarding field analyzer for scanning probe energy loss spectroscopy measurements is described. Using the scanning tunneling microscope (STM) tip as a field emission (FE) electron source in conjunction with this analyzer, which is placed at a glancing angle to the surface plane, FE sample current and electron reflectivity imaging may be performed simultaneously. This is demonstrated in measurements of Ag nanostructures prepared on graphite by electron-beam lithography, where a material contrast of 13% is observed, with a lateral resolution of 25 nm, between the silver and graphite in electron reflectivity images. Topological contrast mechanisms such as edge enhancement and shadowing are also observed, giving rise to additional features in the electron reflectivity images. The same instrument configuration has been used to measure electron energy loss spectra on bare graphite, where the zero loss peak, π band plasmon loss peak and secondary electron peaks are observed. Using this simple and compact analyzer an STM, with sufficient open access to the tip-sample junction, may easily be augmented to provide simultaneous elemental and topographic mapping, supplementing STM image measurements with FE sample current and electron reflectivity images, as well as electron energy loss spectroscopy measurements, in the same instrument.
一种用于扫描探针能量损失谱测量的紧凑型近程延迟场分析仪。使用扫描隧道显微镜 (STM) 尖端作为场发射 (FE) 电子源，结合放置在与表面平面成掠角的分析仪，可同时进行 FE 样品电流和电子反射率成像。这在通过电子束光刻制备的 Ag 纳米结构的测量中得到了证明，在电子反射率图像中观察到银和石墨之间的材料对比度为 13%，横向分辨率为 25nm。还观察到拓扑对比机制，如边缘增强和阴影，导致电子反射率图像中出现额外特征。相同的仪器配置也用于测量裸石墨上的电子能量损失谱，其中观察到零损耗峰、π 带等离子体损耗峰和二次电子峰。使用这种简单紧凑的分析仪和具有足够的尖端-样品结开放通道的 STM，可以很容易地扩展以提供同时的元素和形貌映射，在同一仪器中用 FE 样品电流和电子反射率图像以及电子能量损失谱测量补充 STM 图像测量。
