Annealing Effects on Electrical Properties and Defects of CaCu3Ti4O12 Thin Films Deposited by Pulsed Laser Deposition

AbstractWe present a systematic study of semiconductor and dielectric properties as a function of annealing treatments at CCTO thin films deposited by pulsed laser deposition at 720 °C in 200 mTorr oxygen. The as-deposited thin film samples contain a high concentration of defects that contribute to the semiconductivity in the interior of grains. With increasing annealing temperature, the apparent dielectric constant decreases, and the resistance increases, both at a given temperature (e.g. room temperature). After annealing at 680oC, the semiconductivity was almost completely suppressed and CaCu3Ti4O12 behaved as a dielectric material. Knowing that oxygen vacancies are removed during annealing, one can infer that the dopant states are related to oxygen vacancies. A double plateau behavior in the dielectric constant vs temperature graph indicates that there are at least two defect levels in CaCu3Ti4O12 thin films. This was confirmed by simulating the capacitance response of a Schottky barrier containing two defect levels. Apart of the usual acceptor level, a trap at 500 meV from the valence band was identified. The finally achieved quasi intrinsic material exhibits a negative temperature dependency of the dielectric constant below 120 K.

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Microstructural and Electrical Characterization of Barium Strontium Titanatebased Solid Solution Thin Films Deposited on Ceramic Substrates by Pulsed Laser Deposition

MRS Proceedings ◽

10.1557/proc-720-h2.4 ◽

2002 ◽

Vol 720 ◽

Author(s):

Costas G. Fountzoulas ◽

Daniel M. Potrepka ◽

Steven C. Tidrow

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Pulsed Laser Deposition ◽

Pulsed Laser ◽

Electrical Characterization ◽

Field Variable ◽

Laser Deposition ◽

X Ray Diffraction ◽

Ceramic Substrates ◽

Nominal Thickness

AbstractFerroelectrics are multicomponent materials with a wealth of interesting and useful properties, such as piezoelectricity. The dielectric constant of the BSTO ferroelectrics can be changed by applying an electric field. Variable dielectric constant results in a change in phase velocity in the device allowing it to be tuned in real time for a particular application. The microstructure of the film influences the electronic properties which in turn influences the performance of the film. Ba0.6Sr0.4Ti1-y(A 3+, B5+)yO3 thin films, of nominal thickness of 0.65 μm, were synthesized initially at substrate temperatures of 400°C, and subsequently annealed to 750°C, on LaAlO3 (100) substrates, previously coated with LaSrCoO conductive buffer layer, using the pulsed laser deposition technique. The microstructural and physical characteristics of the postannealed thin films have been studied using x-ray diffraction, scanning electron microscopy, and nano indentation and are reported. Results of capacitance measurements are used to obtain dielectric constant and tunability in the paraelectric (T>Tc) regime.

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Nanostructured LaFeO3 /Si Thin Films Grown by Pulsed Laser Deposition

The European Physical Journal Applied Physics ◽

10.1051/epjap/2021210195 ◽

2021 ◽

Author(s):

Mateusz Jędrusik ◽

Christian Turquat ◽

Łukasz Cieniek ◽

Agnieszka Kopia ◽

Christine Leroux

Keyword(s):

Thin Films ◽

Pulsed Laser Deposition ◽

Deposition Temperature ◽

Oxygen Vacancies ◽

Pulsed Laser ◽

Laser Deposition ◽

Chemical Formula ◽

Iron Deficient ◽

Exposed Facets

The orthorhombic LaFeO3 thin films grown by pulsed laser deposition on silicon showed nano-structuration of their surface and preferential crystallographic exposed facets, depending on the deposition temperature. The LaFeO3 film deposited at 850°C has two types of grain termination, flat or tip-like, corresponding to two different growth directions, respectively [110] and [200]. Due to the shape of the termination, the same {110} facets are exposed. The LaFeO3 is iron deficient and consequently contains oxygen vacancies, the exact chemical formula being LaFe0.82O3-delta.

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High-Temperature Ferromagnetism of Zn1-xMnxOy Thin Films Synthesized by Pulsed Laser Deposition

Materials Science Forum ◽

10.4028/www.scientific.net/msf.989.215 ◽

2020 ◽

Vol 989 ◽

pp. 215-220

Author(s):

A.S. Kuz'mina ◽

M.P. Kuz'min

Keyword(s):

Thin Films ◽

High Temperature ◽

Pulsed Laser Deposition ◽

Oxygen Vacancies ◽

Pulsed Laser ◽

Laser Deposition ◽

Ferromagnetic Behavior ◽

Synthesis Conditions ◽

Semiconductor Matrix ◽

Crystallite Sizes

The paper discusses the findings of the study of the structural and magnetic properties of Zn1-xMnxOy thin films (x = 0-0.08), synthesized by pulsed laser deposition under different conditions. It has been discovered that during the doping, thin films remain single-phased and retain wurtzite structure (ZnO wurz), oriented along the direction (001). It has been determined that thin films obtained under the same synthesis conditions have similar crystallite sizes, which is confirmed by the substitution of Mn2+ ions with Zn2+ ions in the Zn O semiconductor matrix. It has been found that annealing of samples in the oxygen atmosphere increases the surface roughness from 1-3 nm to ~ 10 nm; the higher the concentration of manganese in Zn1-xMnxOy films is, the greater the value of Ra. It has been demonstrated that, at room temperature, all Zn1-xMnxOy thin films (x = 0-0.08) exhibit ferromagnetic behavior, which is more pronounced upon the increase in concentration of oxygen vacancies and manganese in the samples. It is assumed that two mechanisms explaining high-temperature ferromagnetism coexist in the films: the first one is determined by ferromagnetic exchange between Mn2+ cations by means of oxygen vacancies, the second one deals with super-exchange interaction between oxygen vacancies.

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Epitaxial thin films of the giant-dielectric-constant material CaCu3Ti4O12 grown by pulsed-laser deposition

Applied Physics Letters ◽

10.1063/1.1506951 ◽

2002 ◽

Vol 81 (11) ◽

pp. 2056-2058 ◽

Cited By ~ 122

Author(s):

W. Si ◽

E. M. Cruz ◽

P. D. Johnson ◽

P. W. Barnes ◽

P. Woodward ◽

...

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Pulsed Laser Deposition ◽

Pulsed Laser ◽

Laser Deposition ◽

Epitaxial Thin Films ◽

Giant Dielectric ◽

Giant Dielectric Constant

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Sr2MgMoO6−δ thin films fabricated using pulsed-laser deposition with high concentrations of oxygen vacancies

Applied Physics Letters ◽

10.1063/1.4886136 ◽

2014 ◽

Vol 104 (26) ◽

pp. 261901 ◽

Cited By ~ 1

Author(s):

K. Shigematsu ◽

A. Chikamatsu ◽

T. Fukumura ◽

S. Toyoda ◽

E. Ikenaga ◽

...

Keyword(s):

Thin Films ◽

Pulsed Laser Deposition ◽

Oxygen Vacancies ◽

Pulsed Laser ◽

Laser Deposition ◽

High Concentrations

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Dielectric Susceptibility and Strain in Sr1-XBaXTio3 Ferroelectric Thin Films Grown by Pulsed Laser Deposition

MRS Proceedings ◽

10.1557/proc-388-73 ◽

1995 ◽

Vol 388 ◽

Cited By ~ 8

Author(s):

L.A. Knauss ◽

J.S. Horwitz ◽

D.B. Chrisey ◽

J.M. Pond ◽

K.S. Grabowski ◽

...

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Temperature Dependence ◽

Pulsed Laser Deposition ◽

Lattice Mismatch ◽

Bulk Material ◽

Pulsed Laser ◽

Laser Deposition ◽

Dielectric Susceptibility ◽

X Ray

AbstractThin films of Srl-xBaxTiO3 (SBT) with x = 0 to 0.80 have been grown in situ by pulsed laser deposition onto single crystals of (001) LaAlO3. the films were grown to thicknesses of 0.6 μ.m and found to be single phase, highly oriented, and characterized by x-ray ω scan widths of ≤ 0.5°. the temperature dependence of the dielectric constant and the relative dissipation factor were measured at 1 kHz using au interdigital capacitors deposited on top of the ferroelectric films. the capacitance measurements indicate that the temperature dependence of the dielectric constant of the film is broad and the maximum is shifted relative to the bulk material. the differences between thin film and bulk properties are attributed to strain in the film resulting from film -substrate lattice mismatch. Thick films (∼7 μm) gave direct evidence for strain through cracking and delamination. X-ray diffraction measurements have been made to determine the non-uniform strain in the thin films which was approximately 0.1%.

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