Epitaxial VO_(2)films grown by pulsed laser deposition(PLD)method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the“impedance loaded SAW se...Epitaxial VO_(2)films grown by pulsed laser deposition(PLD)method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the“impedance loaded SAW sensor”.A resistance of VO2 sensor abruptly drops from 0.7 MΩto 90Ωwhen it is heated above~65℃and shows a narrow hysteresis loops when switching.Two designs of SAW devices are examined in which RF signal is reflected back from interdigital transducer(IDT)or a surface acoustic waves(SAW)is transferred through a coupler and the RF response is altered 2 and 3 times correspondingly upon the phase transition in VO2.In the proposed devices with external load,a SAW does not propagate via VO2 film and therefore is not attenuated which is beneficiary for wireless applications.Additionally,a SAW phase shift as great as 50°is induced to the SAW transferred through the coupler due to the phase transition in VO2.The proposed approach may boost the development of remotely controlled autonomous sensors,including those based on VO2 metamaterials and hybrid plasmonic structures for near IR/middle IR and sub-THz/THz applications.展开更多
A method for obtaining a new type of surface acoustic wave(SAW)transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally inves...A method for obtaining a new type of surface acoustic wave(SAW)transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally investigated.A method for calculating such a transducer has been developed,its equivalent circuit has been compiled,taking into account propagation losses,losses in the metal film and the inductance of the connecting wires.When the frequency is doubled,the SAW attenuation per unit length increases.展开更多
Efficiency of the piezoelectric chemisensors may be considerably enhanced by use of zinc oxide nanorods as sensing elements.ZnO nanorod arrays being good piezoelectric materials possess large surface area,which provid...Efficiency of the piezoelectric chemisensors may be considerably enhanced by use of zinc oxide nanorods as sensing elements.ZnO nanorod arrays being good piezoelectric materials possess large surface area,which provides extra benefits for chemisorption and photodetection.Highly oriented nanorod arrays are typically prepared onto highly crystalline substrates,whereas the nanorods growth onto metal contacts meets significant technological difficulties.In this paper,we report on carbothermal,electrochemical,and hydrothermal techniques of ZnO nanorod arrays synthesis on metal contacts.The optical and structural properties of the obtained nanorods were studied using scanning electron microscopy,X-ray diffraction(XRD),Raman spectroscopy,and lumi-nescence spectroscopy.A reliable technique was developed for obtaining ohmic contact with the grown nanorods.I-U curves of prepared contact were studied.Carbothermal synthesis made it possible to obtain the most crystallinely perfect,homogeneous,and dense arrays of nanorods and control the concentration of point defects by changing the synthesis parameters over a wide range.The electrochemical synthesis demonstrated excellent results for synthesis of ZnO nanorods on the surface of resonator electrodes.展开更多
A tunable high-Q surface acoustic wave(SAW)resonator in the form of several parallel-connected interdigital transducers loaded on a varying capacitance on lithium niobate substrates was developed and studied.The worki...A tunable high-Q surface acoustic wave(SAW)resonator in the form of several parallel-connected interdigital transducers loaded on a varying capacitance on lithium niobate substrates was developed and studied.The working frequency range was 90-2450 MHz.A method of calculating such resonators,considering losses in the metal film as well as losses due to the propagation of SAWs and transformations into bulk waves is proposed.Such a design allows one to obtain a quality factor over 5000 in the frequency range 2400-2483 MHz.The resonant frequency shifts by 600 kHz when the capacitance changes by±25%of the value of 21 pF(or 32 ppm/pF)and has an almost linear character.展开更多
The aim of this study is to optimize the conditions for producing thin VO_(2)films for their use in SAW devices.We used the pulsed laser deposition(PLD)method to produce VO_(2)films.We used a metallic vanadium target....The aim of this study is to optimize the conditions for producing thin VO_(2)films for their use in SAW devices.We used the pulsed laser deposition(PLD)method to produce VO_(2)films.We used a metallic vanadium target.The dependence of the oxygen pressure during PLD on the resistive metal-insulator transition(MIT)on substrates of c-sapphire and LiNbO_(3)YX/128°was studied.The resulting films had sharp metal-insulator temperature transitions on c-Al_(2)O_(3).The most high-quality films showed resistance change by four orders of magnitude.At the lower point of the hysteresis,the resistance of these samples was in the range of 50-100Ω.The synthesized VO_(2)films had a sharp temperature transition and a relatively small width of thermal hysteresis.The SAW damping during its passage through a VO_(2)/ZnO/LiNbO_(3)YX/128°film at the metal-insulator phase transition temperature was studied.Attenuation SAW decreases with increasing temperature from 52 dB/cm to 0 dB/cm.展开更多
基金supported by Southern Federal University research project No.07/2020-06-MM and 10th Anniversary International Conference on“Physics and Mechanics of New Materials and Their Applications”(PHENMA 2021-2022).
文摘Epitaxial VO_(2)films grown by pulsed laser deposition(PLD)method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the“impedance loaded SAW sensor”.A resistance of VO2 sensor abruptly drops from 0.7 MΩto 90Ωwhen it is heated above~65℃and shows a narrow hysteresis loops when switching.Two designs of SAW devices are examined in which RF signal is reflected back from interdigital transducer(IDT)or a surface acoustic waves(SAW)is transferred through a coupler and the RF response is altered 2 and 3 times correspondingly upon the phase transition in VO2.In the proposed devices with external load,a SAW does not propagate via VO2 film and therefore is not attenuated which is beneficiary for wireless applications.Additionally,a SAW phase shift as great as 50°is induced to the SAW transferred through the coupler due to the phase transition in VO2.The proposed approach may boost the development of remotely controlled autonomous sensors,including those based on VO2 metamaterials and hybrid plasmonic structures for near IR/middle IR and sub-THz/THz applications.
基金supported by Southern Federal University Research Project No.07/2020-06-MMthe 10th Anniversary International Conference on“Physics and Mechanics of New Materials and Their Applications”(PHENMA 2021-2022).
文摘A method for obtaining a new type of surface acoustic wave(SAW)transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally investigated.A method for calculating such a transducer has been developed,its equivalent circuit has been compiled,taking into account propagation losses,losses in the metal film and the inductance of the connecting wires.When the frequency is doubled,the SAW attenuation per unit length increases.
基金Financial support was provided by the Russian Foundation for Basic Research,project 20-07-00637 A.
文摘Efficiency of the piezoelectric chemisensors may be considerably enhanced by use of zinc oxide nanorods as sensing elements.ZnO nanorod arrays being good piezoelectric materials possess large surface area,which provides extra benefits for chemisorption and photodetection.Highly oriented nanorod arrays are typically prepared onto highly crystalline substrates,whereas the nanorods growth onto metal contacts meets significant technological difficulties.In this paper,we report on carbothermal,electrochemical,and hydrothermal techniques of ZnO nanorod arrays synthesis on metal contacts.The optical and structural properties of the obtained nanorods were studied using scanning electron microscopy,X-ray diffraction(XRD),Raman spectroscopy,and lumi-nescence spectroscopy.A reliable technique was developed for obtaining ohmic contact with the grown nanorods.I-U curves of prepared contact were studied.Carbothermal synthesis made it possible to obtain the most crystallinely perfect,homogeneous,and dense arrays of nanorods and control the concentration of point defects by changing the synthesis parameters over a wide range.The electrochemical synthesis demonstrated excellent results for synthesis of ZnO nanorods on the surface of resonator electrodes.
基金This research work is supported by the Russian Ministry of Science and Higher Education under the project No.16.5405.2017/8.9。
文摘A tunable high-Q surface acoustic wave(SAW)resonator in the form of several parallel-connected interdigital transducers loaded on a varying capacitance on lithium niobate substrates was developed and studied.The working frequency range was 90-2450 MHz.A method of calculating such resonators,considering losses in the metal film as well as losses due to the propagation of SAWs and transformations into bulk waves is proposed.Such a design allows one to obtain a quality factor over 5000 in the frequency range 2400-2483 MHz.The resonant frequency shifts by 600 kHz when the capacitance changes by±25%of the value of 21 pF(or 32 ppm/pF)and has an almost linear character.
基金This research work is supported by Southern Federal University,project No.07/2020-06-MM.
文摘The aim of this study is to optimize the conditions for producing thin VO_(2)films for their use in SAW devices.We used the pulsed laser deposition(PLD)method to produce VO_(2)films.We used a metallic vanadium target.The dependence of the oxygen pressure during PLD on the resistive metal-insulator transition(MIT)on substrates of c-sapphire and LiNbO_(3)YX/128°was studied.The resulting films had sharp metal-insulator temperature transitions on c-Al_(2)O_(3).The most high-quality films showed resistance change by four orders of magnitude.At the lower point of the hysteresis,the resistance of these samples was in the range of 50-100Ω.The synthesized VO_(2)films had a sharp temperature transition and a relatively small width of thermal hysteresis.The SAW damping during its passage through a VO_(2)/ZnO/LiNbO_(3)YX/128°film at the metal-insulator phase transition temperature was studied.Attenuation SAW decreases with increasing temperature from 52 dB/cm to 0 dB/cm.
