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Zhang H, Jimbo Y, Niwata A, Ikeda A, Yasuhara A, Ovidiu C, Kimoto K, Kasaya T, Miyazaki HT, Tsujii N, Wang H, Yamauchi Y, Fujita D, Kitamura SI, Manabe H. High-endurance micro-engineered LaB 6 nanowire electron source for high-resolution electron microscopy. NATURE NANOTECHNOLOGY 2022; 17:21-26. [PMID: 34750559 DOI: 10.1038/s41565-021-00999-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
The size tunability and chemical versatility of nanostructures enable electron sources of high brightness and temporal coherence, both of which are important characteristics for high-resolution electron microscopy1-3. Despite intensive research efforts in the field, so far, only conventional field emitters based on a bulk tungsten (W) needle have been able to yield atomic-resolution images. The absence of viable alternatives is in part caused by insufficient fabrication precision for nanostructured sources, which require an alignment precision of subdegree angular deviation of a nanometre-sized emission area with the macroscopic emitter axis4. To overcome this challenge, in this work we micro-engineered a LaB6 nanowire-based electron source that emitted a highly collimated electron beam with good lateral and angular alignment. We integrated a passive collimator structure into the support needle tip for the LaB6 nanowire emitter. The collimator formed an axially symmetric electric field around the emission tip of the nanowire. Furthermore, by means of micromanipulation, the support needle tip was bent to align the emitted electron beam with the emitter axis. After installation in an aberration-corrected transmission electron microscope, we characterized the performance of the electron source in a vacuum of 10-8 Pa and achieved atomic resolution in both broad-beam and probe-forming modes at 60 kV beam energy. The natural, unmonochromated 0.20 eV electron energy loss spectroscopy resolution, 20% probe-forming efficiency and 0.4% probe current peak-to-peak noise ratio paired with modest vacuum requirements make the LaB6 nanowire-based electron source an attractive alternative to the standard W-based sources for low-cost electron beam instruments.
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Affiliation(s)
- Han Zhang
- Research Center for Advanced Material Characterization, National Institute for Materials Science, Tsukuba, Japan.
| | - Yu Jimbo
- JEOL Ltd, Akishima, Tokyo, Japan
| | | | | | | | - Cretu Ovidiu
- Research Center for Advanced Material Characterization, National Institute for Materials Science, Tsukuba, Japan
| | - Koji Kimoto
- Research Center for Advanced Material Characterization, National Institute for Materials Science, Tsukuba, Japan
| | - Takeshi Kasaya
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Hideki T Miyazaki
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Naohito Tsujii
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Hongxin Wang
- Research Center for Advanced Material Characterization, National Institute for Materials Science, Tsukuba, Japan
| | - Yasushi Yamauchi
- Research Center for Advanced Material Characterization, National Institute for Materials Science, Tsukuba, Japan
| | - Daisuke Fujita
- Research Center for Advanced Material Characterization, National Institute for Materials Science, Tsukuba, Japan
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