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This digest paper reports on the first demonstration of suspended β-Ga2O3 nanostructures and nanomechanical resonators made from single-crystal β-Ga2O3 nanosheets or nanomembranes grown via low pressure chemical vapor deposition (LPCVD) on 3C-SiC epi-layer on Si substrate. These single-crystal β-Ga2O3 drumhead nanomechanical resonators offer robust multimode resonances at frequencies in the range...
We report on the first demonstration of electrothermally tunable graphene nanoelectromechanical resonators via Joule heating. We fabricate single-, bi- and tri-layer graphene resonators (up to 136MHz) to study electrothermal effects on resonance characteristics. The tri-layer graphene resonator exhibits frequency upshift from 9.5MHz to 26.1MHz by electrothermal heating, resulting in tuning range up...
We report on the first single- and few-layer molybdenum disulfide (MoS2) nanoelectromechanical resonators with local electrical gate, and the demonstration of local-gate all-electrical actuation, detection, and tuning of the atomic-layer MoS2 resonators at very high frequency (VHF). These local-gate structures make MoS2 vibrating-channel transistors (VCTs), and facilitate efficient frequency modulation...
MEMS resonators integrated with CMOS feedback networks have a potentially wide field of applications as oscillator circuits in communications and sensor systems. However, considerable advancements to this nascent technology are required to realize such a vision. We present a configurable CMOS chip which facilitates the development of MEMS-referenced oscillators, especially for timing and sensing applications...
We report on characterization of microsale lead zirconate titanate (PZT) thin film cantilevers, by both optical and electrical measurements, for up to the 7th resonance mode in 2kHz to 2MHz frequency range, with quality (Q) factors between 380 and 600. We also calibrate the PZT thin film's inverse piezoelectric coefficient (e31 ≈ −5C/m2). This work presents a multiphysical characterization of important...
We report experimental investigation of resonant responses of molybdenum disulfide (MoS2) nanomechanical resonators at different temperatures. We observe strong temperature hysteresis in measurements. By examining devices with different geometries under different air pressures, we determine that surface adsorption plays an important role in the observed temperature hysteresis. This opens new possibilities...
This digest paper describes the experimental demonstration of two dimensional (2D) microscale ‘Chladni figure’-like patterns [1] of populations of microspheres in liquid using SiC micromechanical resonators. SiC square trampoline resonators (size: 50µm×50µm) exhibit appreciable high frequency multimode resonances when operating in liquid. We are able to manipulate relatively small (1.7µm in diameter)...
We report on experimental study and calibration of temperature coefficient of frequency (TCf) and laser heating effect in two-dimensional (2D) resonators, and through which, a new method for determining thermal expansion coefficient (α) in 2D crystals. We measure the resonance characteristics of the ‘drumhead’ nanomechanical resonators based on molybdenum disulfide (MoS2) using sensitive laser interferometry...
This digest paper reports on the first high-frequency nanomechanical resonators based on molybdenum disulfide (MoS2) crystalline flakes freely-suspended on microtrenches (∼13µm wide and 14µm deep) fabricated on flexible substrate, with bendability and stretchability. Through investigations of the device resonances via optical excitation and detection by ultrasensitive laser interferometry, we first...
This digest paper reports the first experimental exploration of directly culturing and measuring breast cancer cells at single-cell level, on the surfaces of silicon carbide (SiC) microdisk resonators. Enabled by the superior biocompatibility of SiC, individual breast cancer cells are observed to attach and spread on surfaces of SiC devices within only 3 hours of culturing. Multimode resonances at...
This digest paper describes experimental demonstration of high-frequency silicon carbide (SiC) microdisk resonators operating in aquatic environments, including water and water solutions of H2O2 and NH4OH. We demonstrate, for the first time, that center-clamped circular SiC microdisks can preserve multiple robust flexural-mode resonances in water. We have observed strong multimode responses in the...
This digest paper describes an experimental exploration of parametric resonance and amplification effects in a ‘dog-bone’-shaped bulk-mode resonator, enabled by CMOS-MEMS technology, by employing electrical excitation and optical detection. In the initially very stiff bulk-mode resonators where efficient parametric pumping is challenging, we have achieved linear resonance signal amplification with...
We report on the experimental calibration of the temperature coefficient of frequency (TCf) in single crystal 6H-silicon carbide (SiC) microdisk resonators based on a smartcut technology. We vary the temperature (T) from −32ºC to 125ºC while monitoring the undriven thermomechanical multimode resonances of the devices using sensitive optical motion detection. Both torsional mode and flexural mode resonances...
We describe the first experimental investigation of pressure-dependent resonant motions in high-frequency circular drumhead resonators based on atomically-thin molybdenum disulfide (MoS2), which demonstrate attractive performance and potential for pressure sensing. Circular bilayer and trilayer MoS2 membrane resonators with diameter of ∼1.8μm are studied in the pressure range of ∼10mTorr to ∼400Torr...
This paper presents a digital closed loop control method for the sense mode of a mode-matching MEMS vibratory gyroscope. The sense closed loop system reported in our previous work is relatively complex and unreliable due to the existence of notch filter. In this work, a more simple and robust control system is realized with the help of mode-matching control. With a tuning voltage automatically applied...
Square poly cry stalline 3C silicon carbide (poly-SiC) thin diaphragms with large aspect ratios (i.e., side length to thickness: L/t ∼ 600) are explored as a structural material for micromechanical resonators. The effects of varying pressure on the characteristics of multiple resonant modes are studied. Load-deflection tests reveal a Young's modulus of EY = 344 ± 13 GPa and a residual (built-in) stress...
We report on experimental demonstration of a new type of nanomechanical resonators based on very thin silicon carbide (SiC) square membranes. An optical interferometry with a radio-frequency two-port measurement scheme enables sensitive and efficient detection of many vibrational modes of the membranes. Membranes with sizes up to 1mm × 1mm and thicknesses down to t ≤ 500nm, offer very high aspect...
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