Energy-Loss Spectroscopy in a Scanning Electron Microscope

该提案要求为安装在SuperSTEM4上的新型电子能量损失光谱仪（EELS）提供资金，SuperSTEM4是一台日立SU9000高分辨率扫描电子显微镜，是EPSRC国家高级电子显微镜研究机构（NRF） SuperSTEM仪器套件的一部分。为了响应通过持续不断地审查提供给用户社区的能力和服务而确定的需求，SuperSTEM最近在样品制备和上游样品表征的基础设备上进行了大量投资。这项投资旨在确保该设施主要高分辨率仪器的分配波束时间最大化。这包括提供NRF的最新仪器SuperSTEM4，这是一种新型的低压（透射）扫描电子显微镜，或(T)SEM，结合了低于0.2nm的高空间分辨率（在30kV加速电压下）和SEM的灵活性和高通量能力。这项EPSRC核心设备资本奖将升级SuperSTEM4，使其具有传输几何形状的电子能量损失光谱仪，这是SEM的独特功能。这将使该设施的用户在一个高通量、高分辨率的显微镜下，以低于该设施主仪器（0.5-30kV）的主光束加速电压获取样品的光谱信息。SuperSTEM4的stem -a- sem特性为制造样品的初步化学成像开辟了更大的长度尺度，为后续对设施主要仪器的调查提供了更广泛的样品区域的更具代表性的信息。此外，由于仪器上安装了许多sem专用探测器（例如背散射和二次电子探测器），表面和地形信息将与EELS的化学信息同时可用，从而允许材料的多维特征（多个信号实现基于数据融合的分析，通过摄影测量编译2D和3D信息）。由于其冷场发射电子源，SuperSTEM4的原生高分辨率（<0.4eV）也将确保在EELS中获得与更高kv SuperSTEM2相当的化学和键合信息，也直接支持用户在等离子体或电子结构测定领域的高端EELS应用。该设备将有助于支持超过120个活跃用户的整个设施用户群，包括许多早期职业研究人员和在该设施进行项目的博士生，并且它还将吸引能够利用易用性和相对容易满足样品质量要求的广泛研究基地的兴趣。

This proposal requests funding for a novel electron energy loss spectrometer (EELS) to be installed on SuperSTEM4, a Hitachi SU9000 high-resolution scanning electron microscope that is part of the instrumentation suite at SuperSTEM, the EPSRC National Research Facility (NRF) for Advanced Electron Microscopy (EM). In response to needs identified through a continuous and on-going review of capabilities and services offered to its user community, SuperSTEM recently made substantial investments in underpinning equipment for specimen preparation and upstream sample characterisation. This investment was directed at capabilities to ensure allocated beamtime on the Facility's main high-resolution instruments is maximised. This includes the provision of the NRF's newest instrument, SuperSTEM4, which is a novel type of low-voltage (transmission) scanning electron microscope, or (T)SEM, combining a high spatial resolution of below 0.2nm (at 30kV acceleration voltage) with the flexibility and high-throughput capabilities of an SEM. This EPSRC Capital Award for Core Equipment will enable the upgrade of SuperSTEM4 with an electron energy loss spectrometer in transmission geometry, a unique capability in an SEM. This will offer the Facility's users access to spectroscopic information on their samples at primary beam acceleration voltage lower than the Facility's main instrumentation (0.5-30kV), within a high-throughput yet high-resolution microscope. The STEM-in-a-SEM nature of SuperSTEM4 opens up larger length-scales for preliminary chemical imaging of fabricated samples, providing providing more representative information from wider areas of samples for subsequent investigation on the Facility's primary instruments. Furthermore, thanks to the numerous SEM-specific detectors installed on the instrument (e.g. backscattered and secondary electron detectors), surface and topographical information will be available simultaneously with chemical information from EELS, allowing for a multidimensional characterisation of materials (multiple signals enabling data-fusion-based analyses, with 2D and 3D information compiled through photogrammetry). Thanks to its cold-field-emission electron source, the native high resolution of SuperSTEM4 (<0.4eV) will also ensure chemical and bonding information in EELS comparable to the higher-kV SuperSTEM2 is obtained, also directly supporting users for high-end EELS applications, e.g. in the field of plasmonics or electronic structure determination. The equipment will help support the entire facility user base of over 120 active users, including numerous early career researchers and doctoral students with on-going projects at the facility, and it will also attract interest from a broadened research base able to take advantage of ease-of-use and relatively easier-to-meet demands regarding sample quality.