Observation of the early stages of heteroepitactic growth of BaTiO3 thin-films

1990 ◽  
Vol 5 (12) ◽  
pp. 2762-2765 ◽  
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Stoichiometric Composition ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Foil ◽  
Nucleation And Growth ◽  
Small Islands ◽  
Early Stages ◽  
Transmission Electron

Thin-films of barium titanate (BaTiO3) have been deposited onto single-crystal MgO substrates using pulsed-laser ablation. The early stages of film growth have been examined using transmission electron microscopy by deposition of very thin films onto specially prepared electron transparent thin-foil substrates. The films, which were crystalline as deposited and close to stoichiometric composition, were formed by the nucleation and growth of small islands.

Early Stages of Growth of BaTiO3 Thin-Films

1990 ◽  
Vol 200 ◽  
Author(s):  
M. Grant Norton ◽  
Gerald R. English ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Surface Preparation ◽  
Thin Foil ◽  
Stages Of Growth ◽  
Early Stages ◽  
Transmission Electron ◽  
Film Nucleation

ABSTRACTBarium titanate (BaTiO3) is of interest for use in a number of thin-film applications in electronic and optoelectronic devices. For these devices the formation of epitactic films of the correct stoichiometry and phase is essential. The substrate is important during the early stages of growth in the establishment of epitaxy, factors such as lattice mismatch, surface preparation and crystallographic orientation can all affect film nucleation and growth. In this study thin-films of BaTiO3 have been formed using the pulsed-laser ablation technique. The early stages of film growth have been studied directly using transmission electron microscopy by examination of very thin films deposited onto specially prepared electron-transparent thin-foil substrates.

Effect of Substrate on the Early Stages of the Growth of YBa2Cu3O7-δ Thin-Films

1990 ◽  
Vol 191 ◽  
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Growth Process ◽  
Critical Role ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
High Quality ◽  
Ceramic Substrates ◽  
Early Stages ◽  
Substrate Structure ◽  
Transmission Electron

ABSTRACTThe fabrication of high-quality thin-films often depends on the early stages of the growth process during which epitaxy is established. The substrate structure and orientation generally play a critical role at this stage through epitaxy and interaction or reaction. Many different materials are being used as substrates to support thin-films of the YBa2Cu3O7-δ superconductors. In this study the early stages of the growth of YBa2Cu3O7-δ thin-films have been investigated using transmission electron microscopy (TEM). Using pulsed-laser ablation, ultra-thin films were formed directly onto self-supporting, ion-thinned, single-crystal ceramic substrates. The substrates used were (001)-oriented MgO, (001)-oriented SrTiO3 and (001)-oriented LaAlO3.

Microstructure of thin YBa2Cu3O7−δ films

1990 ◽  
Vol 48 (4) ◽  
pp. 8-9
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Weak Link ◽  
Critical Currents ◽  
Weak Links ◽  
High Tc ◽  
Fundamental Interest ◽  
Early Stages ◽  
Transmission Electron ◽  
Patterned Films

The microstructure of superconducting thin-films often strongly influences their electrical properties. The actual microstructure of the film will be dependent on the nucleation and early stages of film growth, although the substrate will also be expected to exert an influence during the early stages of growth by the establishment of epitaxy. The highest critical currents have been obtained with films grown on SrTiO3, however MgO is of fundamental interest because patterned films on MgO have been shown to possess Josephson weak-link structure. The presence of the Josephson weak-links has been correlated with the occurrence of misaligned grains in films grown on MgO. Ultra-thin films of high-Tc superconductors are of interest for understanding the properties of these materials and may also be of use in technical applications.The microstructure of ultra-thin YBa2Cu3O7−δ films prepared by pulsed-laser ablation onto (001)- oriented MgO has been studied using transmission electron microscopy (TEM) and selected-area diffraction (SAD).

Early stages of the growth of BaTiO3 thin films studied by Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 706-707
Author(s):  
M. Grant Norton ◽  
Gerald R. English ◽  
Christopher Scarfone ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Room Temperature ◽  
High Temperature Superconductors ◽  
Pulsed Laser ◽  
Target Material ◽  
Pulsed Laser Ablation ◽  
Cubic Phase ◽  
Transmission Electron ◽  
Tetragonal Form

Barium titanate (BaTiO3) may be used in a number of thin-film applications in electronic and optoelectronic devices. For these devices the formation of epitactic films of the correct stoichiometry and phase is essential. In particular, the tetragonal form of BaTiO3, which is stable at room temperature, exhibits ferro-, pyro- and piezoelectric properties. It is desirable to form films of the tetragonal phase directly and thus to avoid formation of either amorphous or polycrystalline material or to form material of the non-ferroelectric cubic phase. Recently two techniques, pulsed-laser ablation and reactive evaporation, have been used to form BaTiO3 thin-films. In the present study BaTiO3 thin-films have been formed using the pulsed-laser ablation technique. Pulsed-laser ablation is now widely used to produce thin-films of the high temperature superconductors and has many advantages over other techniques, in particular the formation of films which maintain the stoichiometry of the target material and by controlling the processing conditions the formation of films having defined crystalline phases.

Epitaxy of barium titanate thin films grown on MgO by pulsed-laser ablation

1991 ◽  
Vol 6 (10) ◽  
pp. 2022-2025 ◽  
Author(s):  
M. Grant Norton ◽  
Christopher Scarfone ◽  
Jian Li ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Barium Titanate ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Oxygen Stoichiometry ◽  
Ion Channeling ◽  
Transmission Electron ◽  
Film Substrate ◽  
Α Particles

Thin films of barium titanate (BaTiO3) have been deposited by pulsed-laser ablation onto (001)-oriented MgO substrates. The films were epitactic with the c-axis perpendicular to the film-substrate interface, as evidenced by both transmission electron microscopy (TEM) and ion-channeling techniques. The elastic resonance of 3.045 MeV α-particles, generating the 16O(α, α)16O reaction was used to determine the oxygen stoichiometry of the film and the minimum yield based on the oxygen peaks, thereby enabling conclusions to be drawn about the crystalline perfection of the oxygen sublattice.

Synthesis and properties of p-type nitrogen-doped ZnO thin films by pulsed laser ablation of a Zn-rich Zn3N2 target

2007 ◽  
Vol 22 (8) ◽  
pp. 2339-2344 ◽  
Author(s):  
A. Allenic ◽  
W. Guo ◽  
Y.B. Chen ◽  
G.Y. Zhao ◽  
X.Q. Pan ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Zno Thin Films ◽  
Zno Films ◽  
Transmission Electron ◽  
Columnar Grains ◽  
P Type ◽  
20 Nm

Epitaxial ZnO thin films doped uniformly with nitrogen at 1020 atoms/cm3 were fabricated by pulsed laser ablation of a Zn-rich Zn3N2 target. The films grown at 300 °C and annealed at 600 °C in O2 showed p-type conductivity. Two acceptor levels at 105 and 224 meV were determined by temperature-dependent Hall and photoluminescence measurements of the p-type samples. Transmission electron microscopy studies revealed that the p-type ZnO films consist of 10–20 nm columnar grains with a high density of defects and grain boundaries that may facilitate the annihilation of native donors and the activation of acceptors during postdeposition annealing.

Nucleation and Heteroepitaxy of YBa2Cu3O7-δ thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 88-89
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Film Growth ◽  
Thin Foil ◽  
Substrate Material ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Bulk Single Crystal ◽  
Transmission Electron ◽  
Final Sample

The nucleation and heteroepitactic growth of YBa2Cu3O7−δ thin-films has been studied by transmission electron microscopy (TEM). The films were formed by pulsed-laser ablation and then observed in the TEM without further sample preparation. Direct observation of the early stages of film growth is possible due to the utilization of a new specimen-preparation technique. The films were deposited directly onto specially prepared electron-transparent substrates. The substrate material used in this study was single-crystal, (001)-oriented MgO. The thin-foil substrates were prepared from bulk single-crystal substrates in the following manner. Discs of 3mm diameter were cored, polished and dimpled to produce a final sample thickness of 10 - 20μm. The samples were ion milled to perforation using 5 kV Ar+ ions, then chemically cleaned. The cleaned foils were annealed in air at 1350°C for 10min. The annealing temperature is such that sufficient atomic mobility enables the formation of a series of steps on the surface.

Laser-Assisted Synthesis of Amorphous/Pseudoamorphous GaN Thin Films and Nanostructures

2006 ◽  
Vol 317-318 ◽  
pp. 585-588
Author(s):  
Seung Hwan Shim ◽  
Naoto Koshizaki ◽  
Jong Won Yoon ◽  
Kwang Bo Shim
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Laser Ablation ◽  
Chemical Composition ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Laser Energy ◽  
Stoichiometric Composition ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation

Amorphous/pseudoamorphous GaN was prepared by pulsed-laser ablation at room temperature without any heat treatment. The structure and chemical composition of the specimens were systematically investigated. Laser ablation at low Ar pressure (<50Pa) led to deposition of smooth Ga-rich films, which is independent with laser energy. Under same pressures, as laser energy increased, the film stoichiometry changed from Ga-rich to near stoichiometric composition. Varying background Ar pressure strongly affected the product structure showing little effect on the chemical composition. Under higher pressure than 100 Pa, fine nanoparticles with a size of 5 nm rather than films were deposited on substrate due to the increased collision by plume confining. The optical band-gap of the deposited a-GaN is 2.8 eV for thin films and 3.9 eV for nanoparticles.

Influence of the microstructure of Pt/Si substrates on textured growth of barium titanate thin films prepared by pulsed laser deposition

1998 ◽  
Vol 13 (2) ◽  
pp. 368-375 ◽  
Author(s):  
Cheol Seong Hwang ◽  
Mark D. Vaudin ◽  
Peter K. Schenck
Keyword(s):  
Thin Films ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Growth Behavior ◽  
Laser Deposition ◽  
Silicon Substrates ◽  
Epitaxial Relationship ◽  
Si Substrates ◽  
Transmission Electron

Pt-coated silicon substrates with strong (111) Pt texture were annealed in an oxidizing atmosphere at temperatures from 500 °C to 750 °C. BaTiO3 thin films were deposited by pulsed laser ablation on the substrates. Observation by transmission electron microscopy showed that the substrate anneal caused the formation of TiO2 in the Pt layer, accompanied by the formation of a high density of faceted protrusions on the Pt surface, particularly at the higher anneal temperatures. The Pt protrusions had (111) facets, parallel to the substrate surface, on which (100)-oriented BaTiO3 grains were observed. BaTiO3 grains with an epitaxial relationship to the Pt lattice were observed on inclined facets of the Pt protrusions [which were not (111) planes], and also on the nonplanar regions of the Pt surface. These epitaxial BaTiO3 grains had (111) preferred orientation relative to the substrate surface. Thus, the BaTiO3 films displayed bimodal growth behavior, with both (100) texture and (111) epitaxy. We propose a model for this behavior based on surface energy considerations.

Examination of Particles and Outgrowths on the Surface of Epitaxial Yba2Cu3O7 Thin Films

1994 ◽  
Vol 341 ◽  
Author(s):  
M. Grant Norton ◽  
Rand R. Biggers ◽  
I. Maartense ◽  
E. K. Moser ◽  
Jeff L. Brown
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Growth Mechanism ◽  
Film Growth ◽  
Pulsed Laser ◽  
Film Surface ◽  
Nucleation And Growth ◽  
Laser Deposition ◽  
Scanning Probe ◽  
Deposition Parameters

AbstractThe surface morphology of Yba2Cu3O7 thin films formed on (001)-oriented LaAlO3 substrates by pulsed-laser deposition has been examined using electron and scanning probe microscopies. The observed surface features can be divided into two types: particles formed as a result of material (often molten) ejected from the target and outgrowths formed as a result of nucleation and growth processes on the substrate and/or the film surface. Where both types of surface feature occur on a particular film the outgrowths are always more numerous. The density of outgrowths is strongly related to the deposition parameters and, as a consequence, with the film growth mechanism.

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