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Ceguerra AV, Breen AJ, Cairney JM, Ringer SP, Gorman BP. Integrative Atom Probe Tomography Using Scanning Transmission Electron Microscopy-Centric Atom Placement as a Step Toward Atomic-Scale Tomography. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:140-148. [PMID: 33468273 DOI: 10.1017/s1431927620024873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Current reconstruction methodologies for atom probe tomography (APT) contain serious geometric artifacts that are difficult to address due to their reliance on empirical factors to generate a reconstructed volume. To overcome this limitation, a reconstruction technique is demonstrated where the analyzed volume is instead defined by the specimen geometry and crystal structure as determined by transmission electron microscopy (TEM) and diffraction acquired before and after APT analysis. APT data are reconstructed using a bottom-up approach, where the post-APT TEM image is used to define the substrate upon which APT detection events are placed. Transmission electron diffraction enables the quantification of the relationship between atomic positions and the evaporated specimen volume. Using an example dataset of ZnMgO:Ga grown epitaxially on c-plane sapphire, a volume is reconstructed that has the correct geometry and atomic spacings in 3D. APT data are thus reconstructed in 3D without using empirical parameters for the reverse projection reconstruction algorithm.
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Affiliation(s)
- Anna V Ceguerra
- Australian Centre for Microscopy & Microanalysis (ACMM), The University of Sydney, Sydney, NSW2006, Australia
- School of Aerospace, Mechanical and Mechatronic Engineering (AMME), The University of Sydney, Sydney, NSW2006, Australia
| | - Andrew J Breen
- Australian Centre for Microscopy & Microanalysis (ACMM), The University of Sydney, Sydney, NSW2006, Australia
- School of Aerospace, Mechanical and Mechatronic Engineering (AMME), The University of Sydney, Sydney, NSW2006, Australia
| | - Julie M Cairney
- Australian Centre for Microscopy & Microanalysis (ACMM), The University of Sydney, Sydney, NSW2006, Australia
- School of Aerospace, Mechanical and Mechatronic Engineering (AMME), The University of Sydney, Sydney, NSW2006, Australia
| | - Simon P Ringer
- Australian Centre for Microscopy & Microanalysis (ACMM), The University of Sydney, Sydney, NSW2006, Australia
- School of Aerospace, Mechanical and Mechatronic Engineering (AMME), The University of Sydney, Sydney, NSW2006, Australia
| | - Brian P Gorman
- Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO80401, USA
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Highly Sensitive Sputtered ZnO:Ga Thin Films Integrated by a Simple Stencil Mask Process on Microsensor Platforms for Sub-ppm Acetaldehyde Detection. SENSORS 2017; 17:s17051055. [PMID: 28481258 PMCID: PMC5469660 DOI: 10.3390/s17051055] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 04/25/2017] [Accepted: 05/04/2017] [Indexed: 11/30/2022]
Abstract
The integration of a 50-nm-thick layer of an innovative sensitive material on microsensors has been developed based on silicon micro-hotplates. In this study, integration of ZnO:Ga via radio-frequency (RF) sputtering has been successfully combined with a low cost and reliable stencil mask technique to obtain repeatable sensing layers on top of interdigitated electrodes. The variation of the resistance of this n-type Ga-doped ZnO has been measured under sub-ppm traces (500 ppb) of acetaldehyde (C2H4O). Thanks to the microheater designed into a thin membrane, the generation of very rapid temperature variations (from room temperature to 550 °C in 25 ms) is possible, and a rapid cycled pulsed-temperature operating mode can be applied to the sensor. This approach reveals a strong improvement of sensing performances with a huge sensitivity between 10 and 1000, depending on the working pulsed-temperature level.
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