Low-voltage coherent electron imaging based on a single-atom electron

Wei-Tse Chang; Chun-Yueh Lin; Wei-Hao Hsu; Mu-Tung Chang; Yi-Sheng Chen; En-Te Hwu; Ing-Shouh Hwang

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arXiv · 1512.08371

Low-voltage coherent electron imaging based on a single-atom electron

Wei-Tse Chang·Chun-Yueh Lin·Wei-Hao Hsu·Mu-Tung Chang·Yi-Sheng Chen·En-Te Hwu·Ing-Shouh Hwang

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Abstract

It has been a general trend to develop low-voltage electron microscopes due to their high imaging contrast of the sample and low radiation damage. Atom-resolved transmission electron microscopes with voltages as low as 15-40 kV have been demonstrated. However, achieving atomic resolution at voltages lower than 10 kV is extremely difficult. An alternative approach is coherent imaging or phase retrieval imaging, which requires a sufficiently coherent source and an adequately small detection area on the sample as well as the detection of high-angle diffracted patterns with a sufficient resolution. In this work, we propose several transmission-type schemes to achieve coherent imaging of thin materials (less than 5 nm thick) with atomic resolution at voltages lower than 10 kV. Experimental schemes of both lens-less and lens-containing designs are presented and the advantages and challenges of these schemes are discussed. Preliminary results based on a highly coherent single-atom electron source are presented. The image plate is designed to be retractable to record the transmission patterns at different positions along the beam propagation direction. In addition, reflection-type coherent electron imaging schemes are also proposed as novel methods for characterizing surface atomic and electronic structures of materials.

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Wei-Tse Chang, Chun-Yueh Lin, Wei-Hao Hsu, Mu-Tung Chang, Yi-Sheng Chen, En-Te Hwu, Ing-Shouh Hwang. 2015-12-28. Low-voltage coherent electron imaging based on a single-atom electron. https://arxiv.org/abs/1512.08371

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