- Titel
- Highly-asymmetric coupled mechanical oscillator for nanowire deflection detection
- Zitierfähige Url:
- https://nbn-resolving.org/urn:nbn:de:bsz:14-qucosa2-975560
- Erstveröffentlichung
- 2025
- Datum der Einreichung
- 02.09.2024
- Datum der Verteidigung
- 14.03.2025
- Abstract (EN)
- The field of NW technology represents an exciting and steadily growing research area with applications in optics and photonics. NWs grown with bottom-up techniques with atomic-level control lead to pristine single-crystal oscillators that are of special interest as they have high structural quality and nanometric dimensions. The miniaturization of oscillators from micro to nanometric scale provides huge advantages in terms of signal enhancement and ultimately enhanced sensitivity. These distinct characteristics make NW a popular choice for force gradient and mass sensors. The constant demand for state-of-the-art devices for measuring small signals and counteracting the limitations of existing ones necessitates the creation of new detection techniques. Optical and field emission approaches are currently used to detect single NW deflection and oscillation. However, they are challenging for detecting small-diameter NWs, i.e., d < 50 nm, because of the heat produced by the laser beam and the impact of the high electric field. Alternatively, the deflection of a NW can be detected indirectly by co-resonantly coupling the NW to a microcantilever and measuring its indirect response on the microcantilever using a scanning probe microscope. In this work, we designed a highly asymmetric co-resonantly coupled oscillator system by coupling the fundamental flexural modes of a Si NW with a silicon microcantilever. We show experimental and theoretical results demonstrating that co-resonantly coupled devices are sensitive to small force derivatives, similar to standalone NWs. We detect force derivatives as small as 10⁻⁹ N/m with a bandwidth of 1 Hz at room temperature in a scanning probe microscopy set up. This work also reports beyond state-of-the-art super-soft nanowire manipulation inside a scanning electron microscope. Furthermore, the measured hybrid vibration modes clearly display signs of avoided crossing, which are controlled by external perturbations such as bias voltage. Additionally, this technique shows the highest possible technical simplicity for single NW deflection detection in comparison to the other existing techniques. The detection technique presented in this work verifies a major step in boosting non-invasive NW-based force and mass sensing capable of operating in a wide range of temperatures, with even further scope for improvement.
- Freie Schlagwörter (EN)
- NEMS/MEMS, coupled cantilever oscillator, co-resonance coupling, nanowire detection, force sensing, real-time frequency detection
- Klassifikation (DDC)
- 530
- Klassifikation (RVK)
- UM 4250
- GutachterIn
- Prof. Dr. Bernd Büchner
- Prof. Dr. Jan Mehner
- BetreuerIn Hochschule / Universität
- Prof. Dr. Bernd Büchner
- BetreuerIn - externe Einrichtung
- Dr. Thomas Mühl
- Den akademischen Grad verleihende / prüfende Institution
- Technische Universität Dresden, Dresden
- Förder- / Projektangaben
- Deutsche Forschungsgemeinscha ID: MU 1794/13-2
- Sonstige beteiligte Institution
- Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden - IFW, Dresden
- Version / Begutachtungsstatus
- publizierte Version / Verlagsversion
- URN Qucosa
- urn:nbn:de:bsz:14-qucosa2-975560
- Veröffentlichungsdatum Qucosa
- 26.06.2025
- Dokumenttyp
- Dissertation
- Sprache des Dokumentes
- Englisch
- Lizenz / Rechtehinweis
CC BY-NC-ND 4.0- Inhaltsverzeichnis
Contents Acknowledgement Abstract 1 Introduction 2 Literature review 2.1 Electron beam-based detection 2.2 Optical detection 2.3 Field emission-based detection 2.4 Other detection techniques 3 Theoretical framework 3.1 Euler-Bernoulli beam theory 3.2 Free oscillations of beams 3.3 Lumped-parameter model of oscillator 3.3.1 Single oscillator 3.3.2 Coupled oscillator 3.4 Frequency tuning 3.5 Noise in MEMS/NEMS oscillators 3.5.1 Johnson-Nyquist noise 3.5.2 Hooge noise 3.5.3 Thermomechanical noise 3.6 Co-resonance concept 4 Experimental methodologies 4.1 Electron-ion microscopy 4.1.1 Matter interaction and resolution 4.1.2 Ion beam induced milling 4.1.3 Real-time frequency detection of oscillators 4.1.4 Optimizing SEM for nano-manipulation 4.2 Scanning probe microscopy 4.3 Tools for nanomanipulation 4.3.1 Electrochemical etching of tungsten tips 4.3.2 Custom-made mounting stage for coupled devices 4.3.3 Nano-manipulator 5 Mechanical instability of nanowires in SEM-based manipulation 5.1 Picking of nanowires 5.2 Placing and releasing of nanowires 5.3 State of the art 6 Force sensing using coupled cantilever sensor 6.1 Oscillator devices 6.1.1 Monolithic silicon cantilever 6.1.2 Silicon nanowires 6.2 Fabrication of coupled oscillator devices 6.3 Frequency tuning using FEBID 6.4 Thermal noise measurements 6.5 Frequency tuning via electrostatic interactions 6.5.1 Resonance frequencies of the coupled modes 6.5.2 Electrostatic interaction with the cantilever 6.5.3 Model for electrostatic force acting at the NW 6.5.4 Contact potential difference 6.5.5 Measurement bandwidth 6.6 Minimum measurable force gradient 6.7 Energy dissipation mechanism: Quality factor 7 Outlook 94 7.1 Batch fabrication of the coupled cantilever devices 7.2 V-shaped nanowires for coupled cantilever sensors 7.3 Cantilever magnetometry of nano-crystallites 8 Summary and conclusion Appendix A Results of device #2 B Fundamental resonance frequency of V-shaped and singly clamped NW Bibliography