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Title: Stress compensation for arbitrary curvature control in vanadium dioxide phase transition actuators

Abstract

Due to its thermally driven structural phase transition, vanadium dioxide (VO{sub 2}) has emerged as a promising material for micro/nano-actuators with superior volumetric work density, actuation amplitude, and repetition frequency. However, the high initial curvature of VO{sub 2} actuators severely obstructs the actuation performance and application. Here, we introduce a “seesaw” method of fabricating tri-layer cantilevers to compensate for the residual stress and realize nearly arbitrary curvature control of VO{sub 2} actuators. By simply adjusting the thicknesses of the individual layers, cantilevers with positive, zero, or negative curvatures can be engineered. The actuation amplitude can be decoupled from the curvature and controlled independently as well. Based on the experimentally measured residual stresses, we demonstrate sub-micron thick VO{sub 2} actuators with nearly zero final curvature and a high actuation amplitude simultaneously. This “seesaw” method can be further extended to the curvature engineering of other microelectromechanical system multi-layer structures where large stress-mismatch between layers are inevitable.

Authors:
 [1];  [2];  [3]; ; ; ;  [1];  [2];  [4];  [5]
  1. Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States)
  2. (United States)
  3. (China)
  4. School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)
  5. State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084 (China)
Publication Date:
OSTI Identifier:
22590610
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 2; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; CONTROL; DENSITY; LAYERS; MEMS; PERFORMANCE; PHASE TRANSFORMATIONS; RESIDUAL STRESSES; THICKNESS; VANADIUM OXIDES

Citation Formats

Dong, Kaichen, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, Lou, Shuai, Choe, Hwan Sung, Yao, Jie, Wu, Junqiao, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Liu, Kai, and You, Zheng. Stress compensation for arbitrary curvature control in vanadium dioxide phase transition actuators. United States: N. p., 2016. Web. doi:10.1063/1.4958692.
Dong, Kaichen, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, Lou, Shuai, Choe, Hwan Sung, Yao, Jie, Wu, Junqiao, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Liu, Kai, & You, Zheng. Stress compensation for arbitrary curvature control in vanadium dioxide phase transition actuators. United States. doi:10.1063/1.4958692.
Dong, Kaichen, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, Lou, Shuai, Choe, Hwan Sung, Yao, Jie, Wu, Junqiao, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Liu, Kai, and You, Zheng. Mon . "Stress compensation for arbitrary curvature control in vanadium dioxide phase transition actuators". United States. doi:10.1063/1.4958692.
@article{osti_22590610,
title = {Stress compensation for arbitrary curvature control in vanadium dioxide phase transition actuators},
author = {Dong, Kaichen, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 and State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084 and Lou, Shuai and Choe, Hwan Sung and Yao, Jie and Wu, Junqiao, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 and Liu, Kai and You, Zheng},
abstractNote = {Due to its thermally driven structural phase transition, vanadium dioxide (VO{sub 2}) has emerged as a promising material for micro/nano-actuators with superior volumetric work density, actuation amplitude, and repetition frequency. However, the high initial curvature of VO{sub 2} actuators severely obstructs the actuation performance and application. Here, we introduce a “seesaw” method of fabricating tri-layer cantilevers to compensate for the residual stress and realize nearly arbitrary curvature control of VO{sub 2} actuators. By simply adjusting the thicknesses of the individual layers, cantilevers with positive, zero, or negative curvatures can be engineered. The actuation amplitude can be decoupled from the curvature and controlled independently as well. Based on the experimentally measured residual stresses, we demonstrate sub-micron thick VO{sub 2} actuators with nearly zero final curvature and a high actuation amplitude simultaneously. This “seesaw” method can be further extended to the curvature engineering of other microelectromechanical system multi-layer structures where large stress-mismatch between layers are inevitable.},
doi = {10.1063/1.4958692},
journal = {Applied Physics Letters},
number = 2,
volume = 109,
place = {United States},
year = {Mon Jul 11 00:00:00 EDT 2016},
month = {Mon Jul 11 00:00:00 EDT 2016}
}
  • We present a detailed infrared study of the semiconductor-to-metal transition (SMT) in a vanadium dioxide (VO2) film deposited on silicon wafer. The VO2 phase transition is studied in the mid-infrared (MIR) region by analyzing the transmittance and the reflectance measurements, and the calculated emissivity. The temperature behaviour of the emissivity during the SMT put into evidence the phenomenon of the anomalous absorption in VO2 which has been explained by applying the Maxwell Garnett effective medium approximation theory, together with a strong hysteresis phenomenon, both useful to design tunable thermal devices to be applied for the thermal control of spacecraft. Wemore » have also applied the photothermal radiometry in order to study the changes in the modulated emissivity induced by laser. Experimental results show how the use of these techniques represent a good tool for a quantitative measurement of the optothermal properties of vanadium dioxide based structures.« less
  • A study was made of the influence of structural disorder created by ion bombardment on the temperature dependence of the electrical conductivity sigma and spectral dependence of the absorption coefficient ..cap alpha..(h..omega..) of VO/sub 2/. The results confirmed that the metal--nonmetal transition occurred in a wide range of structural disorder and that the disorder increased the temperature range of the transition ..delta..T/sub t/ and reduced the effective temperature T/sub t//sup eff/. The disorder also reduced the changes in sigma and ..cap alpha.. associated with the phase transition and probably reduced the difference between the lattice parameters in the two phases.more » It was found that the disorder altered the profile of the ..cap alpha..(h..omega..) band corresponding to the fundamental absorption edge at temperatures T« less
  • An experimental investigation was made of the influence of departures from the lattice periodicity on the semiconductor--metal phase transition in VO/sub 2/. There was no definite critical size r of a region with a periodic distribution of atoms (crystallite) below which the phase transition was absent although there were grounds to expect the influence of r on the phase transition in VO/sub 2/ to appear only for very low values of r (amounting to hundreds and, possibly, tens of angstroms). The occurrence of the phase transition was demonstrated for amorphous samples. Deviations from periodicity in the distribution of atoms (reductionmore » in r) broadened the temperature range ..delta..t/sub t/ within which there were changes in the optical and electrical properties associated with the phase transition; moreover, departures from periodicity increased the width of the thermal hysteresis region ..delta..t/sub H/ and reduced the effective temperature of the phase transition t/sup eff//sub t/. The increases in ..delta..t/sub t/ and ..delta..t/sub H/ were attributed to, respectively, the spatial inhomogeneity of the factors influencing t/sub t/ and to the thermodynamic nonequilibrium of the state of matter with a disordered distribution of atoms. The lowering of t/sup eff//sub t/ was explained by destabilization of the insulator state because of the destruction of the characteristic low-temperature order of the VV pairs and consequent delocalization of the 3d electrons located near these VV molecules because of the presence of structure defects. The spectrum of the changes in the optical properties at the phase transition was practically the same in polycrystalline and amorphous samples and this, together with the occurrence of the phase transition in the amorphous samples, was evidence of a decisive contribution made to the phase transition (and the associated changes in VO/sub 2/) by the components of the electron structure determined by the short order.« less
  • Results are presented of an investigation of the changes in the absorption ..cap alpha.. and reflection R coefficients of vanadium dioxide single crystals at the semiconductor-metal phase transition over a wide range of photon energies from 0.7 to 6 eV. A discussion of the experimental results is given. The increase in ..cap alpha.. in the region of 3d..-->..3d optical transitions and its decrease in the region of 2p..-->..3d transitions are attributed mainly to a change in the matrix elements M/sub i//sub f/, whose square determines the probability of these transitions. The proposed change in M/sub i//sub f/ is explained bymore » an increase in the degree of hybridization of the 2p (O/sup 2 -/) and 3d (V/sup 4 +/) electronic states in the high-temperature metallic phase. The experimental results on the different effects of the phase transition on the various optical transitions are used to provide a more exact interpretation of the optical properties of VO/sub 2/ and to suggest a possible mechanism for the phase transition in this material. According to this mechanism, the closing of the energy gap and the transition to the metallic state are due to the delocalization of the corresponding electronic states as a result of an increase in the indirect 3d (V/sup 4 +/)-2p (O/sup 2 -/) interaction via phonons. (AIP)« less