Combination of Axial Strain Tuning and Gate Bias Tuning for Carbon Nano Tube Resonators (Scientific Reports on Micro and Nanosystems) - Softcover

Vollmann, Morten

Softcover

ISBN 10: 3866288557 ISBN 13: 9783866288553

Verlag: Hartung-Gorre, 2025

Inhaltsangabe

Carbon nanotube (CNT) resonators exhibit exceptional potential for high-frequency and large-range eigenfrequency tuning, yet practical demonstrations have long been limited by the difficulty of precisely applying axial strain. This thesis overcomes that challenge by introducing a custom micro-electro-mechanical system (MEMS) with chevron-style thermal actuators capable of displacing the CNT’s clamping ends and generating pure tensile strain levels up to 1.4%. By combining this axial strain with gate-bias-induced strain, frequency tuning of 67MHz was achieved, equivalent to over 150% relative tuning, reaching eigenfrequencies over 120MHz across multiple devices. To perform such axially straining experiments, new MEMS structures were designed and fabricated according to design restrictions such as the compatibility with dry-CNT transfer methods. Suspended CNT lengths were between 2 and 4.2 μm with gate distances between 490 nm and 2 μm. Different designs of the actuators, thermally heated by electrical current, showed different ability to displace the ends of the electrodes with an efficiency of between 1 and 2.6 nmA-2. Including semi-conducting behaviour in FEM simulations explained the displacement response to current not just for low temperatures, but across the full operation range. Straining experiments on the new MEMS platform included the analysis of the static strain response with gauge factors up to 108 for low gate biases, isolating the axial straining effect from gate bias straining and the combination of both. A central contribution of this work is the detailed modelling of CNT resonators subject to uniaxial and/or gate bias induced straining. The modelling framework employs solutions to the nonlinear Duffing equation via harmonic balancing, a technique that captures both amplitude and phase behaviour of the resonator’s motional current. By including the transfercharacteristic directly into to modelling of the current, even more complex and asymmetric phases and different shapes of resonance peak were explained. This approach proves indispensable for accurately describing the interplay between electrostatic (gate) and mechanical (axial) strain, enabling detailed predictions of device performance. This has been possible only due to the knowledge of applied strain from the characterized actuators. The framework also allowed for the quantification of maximum axial strain of 1.4% before the CNT slipped from the electrodes.

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Über die Autorin bzw. den Autor

Micro and Nanosystems, ETH Zurich, Switzerland PhD Dissertation "Combination of Axial Strain Tuning and Gate Bias Tuning for Carbon Nano Tube Resonators" Department of Mechanical Engineering, EPF Lausanne, Switzerland MSc in Mechanical Engineering TU Berlin, Germany, BSc in Engineering Science, Work Experience 06/2019 - 03/2025 Micro and Nanosystems, ETH Zurich, Switzerland Research and teaching assistant 03/2018 - 10/2018 IBM Research Rueschlikon, Switzerland Research intern 10/2014 - 09/2016 TU Berlin, Berlin, Germany Teaching assistant 03/2015 - 10/2015 The College of New Jersey, Ewing, NJ, USA Research scientist, optical laboratory responsible 08/2012 - 09/2012 Melag Medizintechnik, Berlin, Germany

Details zur Ausgabe

• Verlag: Hartung-Gorre
• Erscheinungsdatum: 2025
• Sprache: Englisch
• ISBN 10: 3866288557
• ISBN 13: 9783866288553
• Einband: Taschenbuch
• Anzahl der Seiten: 216
• Herausgeber: Hierold Christofer
• Kontakt zum Hersteller: preigu GmbH & Co. KG; mail@preigu.de; ; Lengericher Landstr. 19; Osnabrück; Niedersachsen; 49078; Deutschland