Resonance characteristics and energy losses of an ultra-high frequency ZnO nanowire resonator

Abstract

An ultra-high frequency (UHF, 300 MHz ~ 3 GHz) nano mechanical resonator based on defect-free zinc oxide nanowire (ZnO NW) was fabricated through a top-down processing method. Using UHF detection technology based on a lock-in amplifier, through optimized measurement of high-performance equipment, it was detected at room temperature that the ZnO NW resonator could operate at a resonance frequency of nearly 650 MHz and a quality factor Q≈1000~2500, and its force sensitivity could reach 1 f N·Hz-1/2. The deformation, driving force and first-order resonance frequency of the resonator were calculated using the continuum model and compared with the experimental data. The resonance characteristics of ZnO NW resonators under piezoelectric excitation were analyzed and compared with that under electromagnetic excitation. The effects of various loss factors on the resonance characteristics were analyzed, with emphasis on the generation mechanism of piezoelectric loss, clamping loss and eddy current loss and their effects on quality factor and force sensitivity. The ZnO NWs used in this paper have piezoelectric effect, which is rare in other NWs, and are difficult to be fabricated in a bottom-up manner. And experiments show that for ZnO NWs resonators, piezoelectric excitation has obvious advantages in Q value compared with electromagnetic excitation. Unlike the bottom-up wet etch processing method, the resonant beam structure is well protected by the top-down processing method to reduce internal defects, and the top-down fabrication method is easier to integrate into the fabrication process of integrated circuits, which provides great potential for the applications of NW resonators, such as quantum electromechanical systems and high-frequency signal processing.

Flexural-Mode Piezoelectric Resonators: Structure, Performance, and Emerging Applications in Physical Sensing Technology, Micropower Systems, and Biomedicine

“…[59]. (c,d) The structure and mechanical model of the piezoelectrically excited ZnO NW, respectively [21]. (e) Resonator for monitoring the mass accumulation rate of single cells [67].…”

“…Using a one-dimensional piezoelectric resonator with two fixed ends as a reference, the piezoelectric damping constant can be expressed as [21]…”

“… ( a ) SEM image of a stand-alone AlN-on-Si micromechanical resonator and ( b ) the flexural-mode characteristics of thin-film circular membrane resonator [ 59 ]. ( c , d ) The structure and mechanical model of the piezoelectrically excited ZnO NW, respectively [ 21 ]. ( e ) Resonator for monitoring the mass accumulation rate of single cells [ 67 ].…”

“…The red curve is the fitting curve of the blue data points, showing the fitted mode-shape profile of the device [ 68 ]. ( h ) Effect of piezoelectric excitation voltage on output current and dissipation of the ZnO NWs resonator [ 21 ].…”

“…Among them, FMRs have gained extensive application across diverse fields due to their miniature, precise, and efficient performance [8][9][10][11].They are extensively used in microelectronics [12,13], micromechanics [14,15], biomedicine [16,17], and chemical sensing [18,19], providing significant technical support for research and development in these areas. FMRs can be classified into groups of electrostatic excitation [20], electromagnetic excitation [21], piezoelectric excitation [7], and thermal excitation [22] based on the mode of excitation. Piezoelectric excitation, with its high energy density, ease of integration, frequency scaling, simple measurement, and low power consumption configuration, makes piezoelectric an attractive solution for various applications, such as sensors [19,23], actuators [24,25], energy harvesters [26,27], communication modules [28,29], etc.…”