Field Emission Based Displacement Sensing Using a Carbon Nanotube Enhanced Electromechanical Probe
| dc.contributor.advisor | Alemán, Benjamín | |
| dc.contributor.author | Resch, Rudolph | |
| dc.date.accessioned | 2020-09-24T17:11:14Z | |
| dc.date.available | 2020-09-24T17:11:14Z | |
| dc.date.issued | 2020-09-24 | |
| dc.description.abstract | The simple measurement of a distance has long powered sensitive scientific instruments. In the case of scanning probe microscopy (SPM), instruments like Scanning Tunneling Microsopes (STM) and Atomic Force Microscopes (AFM) are powered by ultra-sensitive rulers, measuring atomic-scale distances between their probes and the surface. These instruments opened the doors to direct investigation of the nanoscale world. A decade before, however, was a long forgotten instrument known as the Topografiner. Unlike STM and AFM, the Topografiner used an incredibly sensitive long-range ruler based on a field emission current produced by a sharp metal tip. Most importantly, the long range allows for non-contact investigations of topography and surface properties. Unfortunately, the noisy dc field emission techniques used in its operation and the tip-geometry hindered the potential of the technique to reach atomic-scale resolution. We address these issues by using a high-aspect-ratio carbon nanotube as a field emitter and leverage ac electromechanical coupling to incorporate phase locked loop measurement techniques.These together form a new platform for high precision displacement sensing. We achieve vertical displacement sensing with sub-atomic resolution at room temperature, with a position sensitivity of η=700±400 fm/√Hz while the emitter is located at z~250 nm from the surface, and η~100 pm/√Hz at z~1 μm. This displacement sensitivity approaches that of AFM and STM, with the advantage of a long working distance and large dynamic range. Our electromechanical model shows this improved performance is due to the large aspect ratio and nanometer scale dimensions of the nanotube. The revived topografiner will enable atomic-resolution, high dynamic range SPM imaging, and could also be used to measure and map driven nanomechanical systems or subsurface metallic structures. This dissertation contains previously unpublished co-authored material. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/25604 | |
| dc.language.iso | en_US | |
| dc.publisher | University of Oregon | |
| dc.rights | All Rights Reserved. | |
| dc.subject | Carbon Nanotubes | en_US |
| dc.subject | Displacement Sensing | en_US |
| dc.subject | Field Emission | en_US |
| dc.subject | Nano Electromechanical Systems (NEMS) | en_US |
| dc.subject | Scanning Probe Microscopy | en_US |
| dc.subject | Topografiner | en_US |
| dc.title | Field Emission Based Displacement Sensing Using a Carbon Nanotube Enhanced Electromechanical Probe | |
| dc.type | Electronic Thesis or Dissertation | |
| thesis.degree.discipline | Department of Physics | |
| thesis.degree.grantor | University of Oregon | |
| thesis.degree.level | doctoral | |
| thesis.degree.name | Ph.D. |
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