Microstructure/dielectric property relationship of low temperature synthesised (Na,K)NbOx thin films

Kugler, Veronika; Söderlind, Fredrik; Mušić, Denis; Helmersson, Ulf; Andréasson, Johanna; Lindbäck, Ture

doi:10.1016/j.jcrysgro.2003.10.035

Cited by 15 publications

(10 citation statements)

References 19 publications

(24 reference statements)

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“…Processing under reduced pressure and temperature suggested that the deficiency is not a result of the heat treatment but the sputtering process 179 . Dielectric constants of about 500 are reported 180 . Films of KNN without deficiency of alkali elements can be achieved by adjusting the ratio K:Na:Nb in the target material to 1.5:1.5:1 181 .…”

Section: Sodium Potassium Niobate and Related Materialsmentioning

confidence: 99%

Perspective on the Development of Lead‐free Piezoceramics

Rödel

Seifert

et al. 2009

Journal of the American Ceramic Society

2,673

1,573

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A large body of work has been reported in the last 5 years on the development of lead-free piezoceramics in the quest to replace lead-zirconate-titanate (PZT) as the main material for electromechanical devices such as actuators, sensors, and transducers. In specific but narrow application ranges the new materials appear adequate, but are not yet suited to replace PZT on a broader basis. In this paper, general guidelines for the development of lead-free piezoelectric ceramics are presented. Suitable chemical elements are selected first on the basis of cost and toxicity as well as ionic polarizability. Different crystal structures with these elements are then considered based on simple concepts, and a variety of phase diagrams are described with attractive morphotropic phase boundaries, yielding good piezoelectric properties. Finally, lessons from density functional theory are reviewed and used to adjust our understanding based on the simpler concepts. Equipped with these guidelines ranging from atom to phase diagram, the current development stage in lead-free piezoceramics is then critically assessed.

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Section: Sodium Potassium Niobate and Related Materialsmentioning

confidence: 99%

Perspective on the Development of Lead‐free Piezoceramics

Rödel

Seifert

et al. 2009

Journal of the American Ceramic Society

2,673

1,573

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“…Previous studies on the RF magnetron sputtering of KNN thin films have shown that the composition and the growth rate of the KNN thin films are not influenced by the growth temperature. 17,18,24 Furthermore, the crystalline orientation of the KNN thin films was proven to be dependent on the growth temperature. To substantiate this hypothesis and to test the primary premise that the RF plasma can determine the alkali ratios (and thereby, film composition), we carried out depositions on a modified substrate and at a lower temperature.…”

Section: As-grown 1 H Vacuum 3 H Vacuum 1 H Oxygenmentioning

confidence: 99%

“…5,[7][8][9][10][17][18][19][20][21][22] Among these, RF magnetron sputtering is promising due to its capability for large area depositions with lower growth temperatures that makes it viable for integration with fabrication processes. Major challenges in the RF magnetron sputtering of KNN-based thin films are non-stoichiometry due to the volatility of the alkali metals, 18,23 the formation of secondary phases, 24 and a high leakage current density. 17,18 The loss of alkali metals during the KNN thin film synthesis was noted in the early attempts of PLD and RF magnetron sputtering.…”

Section: Introductionmentioning

confidence: 99%

“…17,23,25 Further studies on the effects of different sputtering parameters on the composition, crystal structure and growth rate of the KNN thin films revealed that while the crystalline phases and growth rate are largely dependent on the sputtering pressure and growth temperature, the alkali loss cannot be controlled by varying the sputtering parameters. 17,18,24 It was suggested then that the alkali volatility can be addressed by excess amounts of the K and Na species (usually in the ratio of 1.5 : 1.5 : 1 for K : Na : Nb) in the sputtering targets. 23 Most recently, Kim et al 22 have studied the effect of the post-annealing treatment on the crystal structure and electrical properties of KNN thin films grown on Pt/Ti/SiO 2 /Si substrates at a substrate temperature of 300 uC utilizing a stoichiometric target, in different annealing atmospheres.…”

Section: Introductionmentioning

confidence: 99%

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Alkali ratio control for lead-free piezoelectric thin films utilizing elemental diffusivities in RF plasma

et al. 2013

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High performance piezoelectric thin films are generally lead-based, and find applications in sensing, actuation, and transduction in realms of biology, nanometrology, acoustics, and energy harvesting. Potassium sodium niobate (KNN) is considered to be the most promising lead-free alternative, but is hindered by the inability to control and attain perfect stoichiometry materials in thin film form while using practical large area deposition techniques. In this work, we identify the contribution of elemental diffusivities in radio frequency (RF) plasma in determining alkali loss in KNN thin films. We have also examined the effect of substrate temperature during the RF-magnetron sputtering deposition on the crystal structure of the substrate and KNN thin films, as well as the effect of post-annealing treatments.These results indicate the need for well-designed source materials and the potential to use deposition partial pressures to alter dopant concentrations.

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“…[28][29][30] However, little has been reported on the relative ferroelectric or piezoelectric properties of KNN nanotubes. Figure 4(a) shows the P-E hysteresis loops of the KNN nanotube array measured with different voltage at room temperature while the schematic drawing of measurement configuration is shown in the inset.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, characterization and ferroelectric properties of lead-free K0.5Na0.5NbO3 nanotube arrays

Zhou

et al. 2011

Journal of Applied Physics

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Lead-free K 0.5 Na 0.5 NbO 3 (KNN) nanotube arrays were synthesized by a sol-gel method with anodic aluminum oxide templates. The obtained KNN nanotubes exhibited a polycrystalline and monoclinic perovskite structure with diameters of 200 nm and wall thickness of 30-40 nm, respectively. The polarization-electric loop curve of the nanotubes array were examined showing the values of 2P r and 2E c at about 3.4 lC/cm 2 and 13 kV/cm, respectively, under a maximum electric field of 12.5 kV/cm. The piezoelectric characteristics of individual KNN nanotube array was also identified through piezoresponse force microscopy.

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Microstructure/dielectric property relationship of low temperature synthesised (Na,K)NbOx thin films

Cited by 15 publications

References 19 publications

Perspective on the Development of Lead‐free Piezoceramics

Perspective on the Development of Lead‐free Piezoceramics

Alkali ratio control for lead-free piezoelectric thin films utilizing elemental diffusivities in RF plasma

Synthesis, characterization and ferroelectric properties of lead-free K0.5Na0.5NbO3 nanotube arrays

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