Facile preparation of KNN thin film with high purity phase and excellent electrical properties

Abstract Obtaining high purity alkali niobate (K x Na 1- x NbO 3 ) thin films without secondary phase on metal coated traditional silicon (Si) substrates via sol–gel technique has remained great challenges until now. Herein, we report K 0.5 Na 0.5 NbO 3 (KNN) thin films successfully deposited on Pt/...

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Bibliographic Details
Published in:Advances in natural sciences. Nanoscience and nanotechnology 2024-03, Vol.15 (1), p.15015
Main Authors: Nguyen, Phuong T M, Nguyen, Tai, Vu, Thu-Hien
Format: Article
Language:English
Subjects:
Columnar structure
Dielectric constant
Dielectric loss
Electrical properties
ferroelectric properties
Frequency ranges
Grain size
KNN thin films
Leakage current
leakage current density
Microstructure
Purity
Silicon dioxide
Silicon substrates
sol-gel method
Sol-gel processes
Spin coating
Stoichiometry
Thin films
X ray photoelectron spectroscopy
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Summary:Abstract Obtaining high purity alkali niobate (K x Na 1- x NbO 3 ) thin films without secondary phase on metal coated traditional silicon (Si) substrates via sol–gel technique has remained great challenges until now. Herein, we report K 0.5 Na 0.5 NbO 3 (KNN) thin films successfully deposited on Pt/Ti/SiO 2 /Si(100) substrates by a simply effective sol–gel process. A comprehensive and systematic investigation of processing conditions on the microstructures and electrical properties of spin-coated KNN films was presented. We have found that phase purity and microstructures of KNN films are strongly influenced by content of alkali excess and the annealing temperature. Thin films with an equal excess amount of 10% mol K and Na (KNN1) sintered at 650 °C show high crystallinity with a preferred (100)-orientation degree of 78%, and homogeneous and dense surface with columnar structure and large grain size up to 254 nm. The result of quantitative XPS analysis has proved that the composition of the film is close to the chemical stoichiometry. As a consequence, the obtained KNN1 films exhibit a large dielectric constant of 775 and low dielectric loss of ∼2% in the wide frequency range from 1kHz up to 10MHz as well as the best shape of P − E loops. Furthermore, leakage current density of the film is about 9.45 × 10 −5 A cm −2 at E ≈100 kV cm −1 .
ISSN:2043-6262
2043-6254
2043-6262
DOI:10.1088/2043-6262/ad2fb6