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Journal ArticleDOI

UV Light Detection Using Resonance Frequency of Piezoelectric Quartz Crystal

TL;DR: In this article, the authors reported about the ultraviolet radiation effect on the resonance frequency response of AT-cut piezoelectric quartz crystal and showed that a large upshift was observed when the quartz crystal was irradiated by UV light of 355-nm wavelength using a Q-switched pulsed Nd:YVO4 UV laser.
Abstract: This article reported about the ultraviolet (UV) radiation effect on the resonance frequency response of a AT-cut piezoelectric quartz crystal. A large resonance frequency upshift was observed when the quartz crystal was irradiated by UV light of 355-nm wavelength using a Q-switched pulsed Nd:YVO4 UV laser. The dynamic frequency response behavior was systematically investigated by illuminating the quartz crystal with UV light in which the UV intensity was varied with time in staircase- and linear pulse-shaped patterns. From the experimental analysis, we measured the limit of detection and the sensitivity of the quartz crystal, which are about 0.5 mW/cm2 and 0.706 Hz/(mW/cm2), respectively. For a constant UV irradiation, a moderate response (<10 s) and recovery (<10 s) times were achieved during the on and off cycles of the UV light. The short-term repeatability and maximum operating limit of AT-cut quartz crystal were also further studied upon exposure to UV light with different intensities. In this work, we not only demonstrate the impact of UV irradiation on quartz crystal but also discuss the mechanism of upshift in resonance frequency upon exposure to UV light. This study shows the applicability of quartz crystal for the detection of UV light.
Citations
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Journal ArticleDOI
TL;DR: In this article , the effect of the oxide film is up to a fourfold increase in quality factor (Q) that is consistent from very high frequency (VHF) to super-high frequency (SHF) using thin plate bulk acoustic wave modes from 70-80 MHz using the second contour mode and first width extensional mode and from 9.5-10.5 GHz using high overtone thickness modes.
Abstract: Piezoelectric microelectromechanical systems (MEMS) are used as sensors, actuators, energy harvesters, accelerometers, and communication modules. Aluminum nitride (AlN) is an especially attractive piezoelectric material because its fabrication process allows it to be integrated into semiconductor circuitry to deliver a fully integrated solution. Microelectromechanical resonators with AlN sandwiched between n‐type silicon (Si) and top metal electrode with and without a silicon oxide layer are designed and fabricated. The effect of the oxide film is up to a fourfold increase in quality factor (Q) that is consistent from very high frequency (VHF) to super high frequency (SHF). This effect is demonstrated using thin plate bulk acoustic wave modes from 70–80 MHz using the second contour mode and first width extensional mode and from 9.5–10.5 GHz using high overtone thickness modes. To explore potential applications of AlN‐transduced Q‐enhanced MEMS devices in harsh environments, measurements from −200 °C to +200 °C are performed. The Q enhancement is persistent across a wide temperature range for both VHF and SHF resonators with the added oxide layer. Furthermore, AlN‐on‐Si resonators that have a comparable temperature coefficient of frequency to silicon carbide‐based resonators in commercial applications are demonstrated.

3 citations

Journal ArticleDOI
TL;DR: In this paper , the effects of radiation on microelectromechanical systems (MEMS) are investigated and a new method is presented of permanent frequency trimming MEMS resonators up to 30% of their bandwidth without modifying quality factor or motional resistance.
Abstract: While much radiation test data are available for metal‐oxide‐semiconductor (MOS) devices, research into the effects of radiation on microelectromechanical systems (MEMS) is in its relative infancy. Piezoelectrically transduced MEMS resonators have broad applications in signal processing, environmental monitoring, and navigation. Aluminum nitride (AlN), in particular, is an attractive piezoelectric because of its favorable fabrication characteristics and ease of integration into the complementary MOS (CMOS) manufacturing process. The utility of these devices in space and nuclear systems necessitates research into their performance in radiation environments. Resiliency and an established relationship between radiation dose and device behavior provide a critical tool for engineers in their design process. Multiple AlN‐based MEMS resonator designs are created and exposed the devices to 1 Mrad(Si) gamma irradiation from a Cobalt‐60 source while measuring scattering (S‐) parameters in situ. The experimental data are matched to a theoretical model to describe the change in frequency as a function of radiation‐induced displacement damage. It is demonstrated that the AlN‐based resonators are resilient against radiation‐induced charge‐trapping effects. Furthermore, a new method is presented of permanent frequency trimming MEMS resonators up to 30% of their bandwidth without modifying quality factor or motional resistance.
Journal ArticleDOI
TL;DR: In this paper , a Lamb wave resonator-based UV photodetector is fabricated using ZnO thin film grown on SiO2/Si membrane, which reveals a change in current ( ${A}_{{2}}{)}
Abstract: In this work, a Lamb wave resonator-based UV photodetector is fabricated using ZnO thin film grown on SiO2/Si membrane. Electrical studies of the fabricated ZnO/SiO2/Si Lamb wave resonator device reveals a change in current ( ${I}_{\text {on}}/{I}_{\text {off}} \sim 10^{{4}}{)}$ upon UV illumination ( $\lambda =365$ nm, Intensity = 0.2 mW/cm $^{{2}}{)}$ with a responsivity (56.34 A/W), detectivity ( ${6}.{5}\times {10} ^{{12}}$ Jones) and response and recovery time of 280 and 25 ms, respectively. Frequency response of the fabricated Lamb wave device demonstrates the presence of multiple modes corresponding to symmetric and anti-symmetric modes and their higher harmonics. It is observed that the highest mode ( ${A}_{{2}}{)}$ of Lamb wave resonator (192.27 MHz) shows maximum frequency shift (535 kHz(mW/cm $^{{2}}{)}^{-{1}}{)}$ and very high sensitivity of $2.78\times 10^{{3}}$ ppm(mW/cm $^{{2}}{)}^{-{1}}$ . In addition, various mechanism involved in the photodetection are being discussed. Especially, the effect of induced piezo-potential on Schottky barrier height (SBH) in the acoustic device and corresponding enhancement in the photodetector performance is discussed. It is observed that Lamb wave device with Schottky contact type IDTs shows higher UV detection performance as compared to the that with Ohmic type IDTs contact. This effect can be explained using effect of induced piezo-potential on SBH while the acoustic wave is propagating in the piezoelectric substrate of the surface acoustic wave (SAW) devices. Thus, the study demonstrates the high potential of indigenously developed Lamb wave resonator-based UV photodetector (ZnO/SiO2/Si) for civil and military field applications.
Journal ArticleDOI
TL;DR: In this paper , a Lamb wave resonator-based UV photodetector is fabricated using ZnO thin film grown on SiO2/Si membrane, which reveals a change in current.
Abstract: In this work, a Lamb wave resonator-based UV photodetector is fabricated using ZnO thin film grown on SiO2/Si membrane. Electrical studies of the fabricated ZnO/SiO2/Si Lamb wave resonator device reveals a change in current ( ${I}_{\text {on}}/{I}_{\text {off}} \sim 10^{{4}}{)}$ upon UV illumination ( $\lambda =365$ nm, Intensity = 0.2 mW/cm $^{{2}}{)}$ with a responsivity (56.34 A/W), detectivity ( ${6}.{5}\times {10} ^{{12}}$ Jones) and response and recovery time of 280 and 25 ms, respectively. Frequency response of the fabricated Lamb wave device demonstrates the presence of multiple modes corresponding to symmetric and anti-symmetric modes and their higher harmonics. It is observed that the highest mode ( ${A}_{{2}}{)}$ of Lamb wave resonator (192.27 MHz) shows maximum frequency shift (535 kHz(mW/cm $^{{2}}{)}^{-{1}}{)}$ and very high sensitivity of $2.78\times 10^{{3}}$ ppm(mW/cm $^{{2}}{)}^{-{1}}$ . In addition, various mechanism involved in the photodetection are being discussed. Especially, the effect of induced piezo-potential on Schottky barrier height (SBH) in the acoustic device and corresponding enhancement in the photodetector performance is discussed. It is observed that Lamb wave device with Schottky contact type IDTs shows higher UV detection performance as compared to the that with Ohmic type IDTs contact. This effect can be explained using effect of induced piezo-potential on SBH while the acoustic wave is propagating in the piezoelectric substrate of the surface acoustic wave (SAW) devices. Thus, the study demonstrates the high potential of indigenously developed Lamb wave resonator-based UV photodetector (ZnO/SiO2/Si) for civil and military field applications.
References
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Journal ArticleDOI
TL;DR: A tutorial review article on the quartz crystal microbalance (QCM) is presented in this paper, followed by a summary of recent and important prior research in each of the different areas of analytical interest in the QCM.

650 citations

Journal ArticleDOI
17 Sep 2010-Sensors
TL;DR: The performance of ZnO-based photodetectors is analyzed, discussing recent achievements, and comparing the characteristics of the variousPhotodetector structures developed to date.
Abstract: Ultraviolet (UV) photodetection has drawn a great deal of attention in recent years due to a wide range of civil and military applications. Because of its wide band gap, low cost, strong radiation hardness and high chemical stability, ZnO are regarded as one of the most promising candidates for UV photodetectors. Additionally, doping in ZnO with Mg elements can adjust the bandgap largely and make it feasible to prepare UV photodetectors with different cut-off wavelengths. ZnO-based photoconductors, Schottky photodiodes, metal–semiconductor–metal photodiodes and p–n junction photodetectors have been developed. In this work, it mainly focuses on the ZnO and ZnMgO films photodetectors. We analyze the performance of ZnO-based photodetectors, discussing recent achievements, and comparing the characteristics of the various photodetector structures developed to date.

558 citations

Journal ArticleDOI
Urs Gysin, S. Rast, P. Ruff, Ernst Meyer, Dong Weon Lee1, Peter Vettiger1, Christoph Gerber1 
TL;DR: In this article, the first eigenmode of microfabricated silicon cantilevers are measured in the temperature range of 15--300 K. The analysis shows that variation of Young's modulus is responsible for the temperature dependence of the resonance frequency, whereas the dependence of geometrical dimensions can be neglected.
Abstract: The resonance frequency $\ensuremath{\omega}$ and internal friction ${Q}^{\ensuremath{-}1}$ of the first eigenmode of microfabricated silicon cantilevers are measured in the temperature range of 15--300 K. The analysis shows that variation of Young's modulus is responsible for the temperature dependence of the resonance frequency, whereas the dependence of the geometrical dimensions can be neglected. Accordingly, the data can be fitted by the Wachtman equation, yielding a Debye temperature ${\ensuremath{\Theta}}_{D}=634\mathrm{K}.$ The temperature variation of internal friction ${Q}^{\ensuremath{-}1}$ is analyzed in terms of Zener's theory of thermoelastic damping. Due to the temperature dependence of the thermal expansion coefficient $\ensuremath{\alpha},$ thermoelastic damping is expected to vanish at 20 K and 125 K. A minimum of internal friction is observed at 20 K, whereas the minimum at 125 K appears to be hidden by other dissipation effects. A maximum of internal friction at 160 K is observed, which is an activation peak due to phonon scattering by atomic-scale defects. The best force sensitivity is achieved at 20 K, where a factor of 10 is gained compared to room temperature.

167 citations

Journal ArticleDOI
TL;DR: There has been an increase in the number of papers published involving piezoelectric acoustic sensors, or quartz crystal microbalances (QCM), when compared to the last period reviewed 2006-2009 as mentioned in this paper.
Abstract: In 2010 there has again been an increase in the number of papers published involving piezoelectric acoustic sensors, or quartz crystal microbalances (QCM), when compared to the last period reviewed 2006-2009. The average number of QCM publications per annum was 124 in the period 2001-2005, 223 in the period 2006-9, and 273 in 2010. There are trends towards increasing use of QCM in the study of protein adsorption to surfaces (93% increase), homeostasis (67% increase), protein-protein interactions (40% increase), and carbohydrates (43% increase). New commercial systems have been released that are driving the uptake of the technology for characterisation of binding specificities, affinities, kinetics and conformational changes associated with a molecular recognition event. This article highlights theoretical and practical aspects of the principals that underpin acoustic analysis, then reviews exemplary papers in key application areas involving small molecular weight ligands, carbohydrates, proteins, nucleic acids, viruses, bacteria, cells, and membrane interfaces.

140 citations

Journal ArticleDOI
TL;DR: In this paper, photoconducting properties of In2O3 nanowires were studied and the use of UV light as a gas cleanser was demonstrated for chemical sensors, leading to a recovery time as short as 80 s.
Abstract: Photoconducting properties of In2O3 nanowires were studied. Devices based on individual In2O3 nanowires showed a substantial increase in conductance of up to four orders of magnitude upon exposure to UV light. Such devices also exhibited short response times and significant shifts in the threshold gate voltage. The sensitivity to UV of different wavelengths was studied and compared. We have further demonstrated the use of UV light as a “gas cleanser” for In2O3 nanowire chemical sensors, leading to a recovery time as short as 80 s.

135 citations