Heteroepitaxy of Strained and Not-Strained Ferroelectric Superlattices and their Electric Properties.

1995 ◽  
Vol 401 ◽  
Author(s):  
Hitoshi Tabata ◽  
Masakazu Hamada ◽  
Tomoji Kawai
Keyword(s):  
Dielectric Constant ◽  
Essential Role ◽  
Ferroelectric Properties ◽  
Coulomb Force ◽  
In Situ Monitoring ◽  
Laser Deposition ◽  
Layer By Layer ◽  
Ferroelectric Films ◽  
Layer Deposition

AbstractBismuth based artificial superlattices have been formed by a layer-by-layer laser deposition with in-situ monitoring of RHEED. The Bi2O2/WO6, Bi2O2/SrTa2O9, Bi2O2/SrTa2O9 /SrTiO3 and Bi2O2/SrTa2O9/BaTiO3 are constructed epitaxially by a single, double and triple perovskite layers sandwiched by Bi2O2 layers, respectively. The dielectric constant increases with increasing the number of perovskite layers. And the D-E hysteresis loop (ferroelectric properties) appears along the c-axis direction in odd perovskite layers (n=l and 3). We have also formed the SrTiO3/BiWO6/SrTiO3 multi layers. With this combination, the STO layers are isolated by the BWO layers. The dimensionality of STO layer can be controlled by changing the thickness of BWO layers. Below the BWO thickness of 500 Å, the εr increases monotonously with decreasing the BWO thickness. Therefore, the the coulomb force, which is in proportion to inverse of the distance, plays an essential role for the dielectric constant. The formation of “artificially constructed ferroelectric films” by a layer-by-layer deposition method will be discussed ad an essential approach to elucidate the mechanism of ferroelectricity.

In situ monitoring of electrical resistivity and plasma during pulsed laser deposition growth of ultra-thin silver films

2021 ◽  
Vol 130 (8) ◽  
pp. 085301
Author(s):  
M. Novotný ◽  
P. Fitl ◽  
S. A. Irimiciuc ◽  
J. Bulíř ◽  
J. More-Chevalier ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
In Situ Monitoring ◽  
Laser Deposition ◽  
Silver Films

scholarly journals A platform for light-controlled formation of free-stranding lipid membranes

2020 ◽  
Vol 17 (163) ◽  
pp. 20190740 ◽  
Author(s):  
Nikolay V. Ryzhkov ◽  
Ekaterina V. Skorb
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Science And Technology Studies ◽  
Separation Distance ◽  
Layer By Layer ◽  
Net Charge ◽  
Novel Approach ◽  
Layer Deposition ◽  
Transmembrane Channels

The engineering of artificial cells is one of the most significant scientific challenges. Thus, controlled fabrication and in situ monitoring of biomimetic nanoscale objects are among the central issues in current science and technology. Studies of transmembrane channels and cell mechanics often require the formation of lipid bilayers (LBs), their modification and their transfer to a particular place. We present here a novel approach for remotely controlled manipulation of LBs. Layer-by-layer deposition of polyethyleneimine and poly(sodium 4-styrenesulfonate) on a nanostructured TiO 2 photoanode was performed to obtain a surface with the desired net charge and to enhance photocatalytic performance. The LB was deposited on top of a multi-layer positive polymer cushion by the dispersion of negative vesicles. The separation distance between the electrostatically linked polyelectrolyte cushion and the LB can be adjusted by changing the environmental pH, as zwitter-ionic lipid molecules undergo pH-triggered charge-shifting. Protons were generated remotely by photoanodic water decomposition on the TiO 2 surface under 365 nm illumination. The resulting pH gradient was characterized by scanning vibrating electrode and scanning ion-selective electrode techniques. The light-induced reversible detachment of the LB from the polymer-cushioned photoactive substrate was found to correlate with suggested impedance models.

Optical in situ monitoring of plasma-enhanced atomic layer deposition process

2018 ◽  
Vol 57 (6S2) ◽  
pp. 06JF05 ◽  
Author(s):  
Muhammad Zeeshan Arshad ◽  
Kyung Jae Jo ◽  
Hyun Gi Kim ◽  
Sang Jeen Hong
Keyword(s):  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Deposition Process ◽  
In Situ Monitoring ◽  
Atomic Layer Deposition Process ◽  
Layer Deposition

Combinatorial optimization of atomically controlled growth for oxide films by the carrousel type laser molecular beam epitaxy

2001 ◽  
Vol 700 ◽  
Author(s):  
R. Takahashi ◽  
Y. Matsumoto ◽  
H. Koinuma ◽  
M. Lippmaa ◽  
M. Kawasaki
Keyword(s):  
Molecular Beam ◽  
Ybco Film ◽  
High Sensitivity ◽  
High Energy ◽  
In Situ Monitoring ◽  
Laser Deposition ◽  
Crystal Habit ◽  
Laser Focusing ◽  
The One

AbstractA new combinatorial pulsed laser deposition system has been developed for rapid optimization of epitaxial growth process by using a carrousel type masking plate. Under in-situ monitoring of growing surface with reflection high energy electron diffraction, eight films with different compositions or preparation parameters can be fabricated on a single substrate. By using this system, we have succeeded in the one lot optimization of YBa2Cu3O7-d(YBCO), PrGaO3, SrO and BaO film growths on the B-site (TiO2) terminated SrTiO3(001) substrates. Key results from these experiments include the high sensitivity of YBCO film crystallinity to the laser focusing as well as of growth behavior of epitaxial SrO and BaO films to the crystal habit with the underlying atomic layers.

In Situ Monitoring in the Pulsed Laser Deposition of Ferroelectric Thin Films

1994 ◽  
Vol 361 ◽  
Author(s):  
Peter K. Schenck ◽  
Mark D. Vaudin ◽  
Byeong W. Lee ◽  
David W. Bonnell ◽  
John W. Hastie ◽  
...  
Keyword(s):  
Thin Films ◽  
Oxygen Content ◽  
Target Surface ◽  
Lattice Parameter ◽  
Ferroelectric Thin Films ◽  
In Situ Monitoring ◽  
Laser Deposition ◽  
Buffer Gas ◽  
Additional Information

ABSTRACTOptical multichannel emission spectroscopie studies and ICCD (intensified charge coupled device) imaging have been applied to real-time, in situ gas phase species identification and plume structure analysis during the pulsed excimer laser deposition (PLD) of various ferroelectric thin films. Additional information on the non-excited plume species has been obtained using molecular beam-sampling mass spectrometry. The materials studied included targets of PbZr0.53Ti0.47O3 (PZT) and BaTiO3. For the BaTiO3 films, the partial pressure of oxygen in the buffer gas and the atomic oxygen emission within the plume both correlated with the observed lattice parameter, as determined by X-ray analysis. Reduced plume oxygen content resulted in an increased lattice parameter that, in turn, could be related to a reduced oxygen content in the film. ICCD imaging of plumes from PZT targets identified the presence of ejected particulates in the plume after multiple laser shots had worked the target surface. Scanning electron microscopy (SEM) studies of the PZT target surface and film morphology, revealed cone-like formations on the target and éjecta on the films which correlated well with the ICCD observation of plume particulates.

scholarly journals Interface Combinatorial Pulsed Laser Deposition to Enhance Heterostructures Functional Properties

2020 ◽  
Author(s):  
Jérôme Wolfman ◽  
Beatrice Negulescu ◽  
Antoine Ruyter ◽  
Ndioba Niang ◽  
Nazir Jaber
Keyword(s):  
Pulsed Laser Deposition ◽  
Functional Properties ◽  
Film Growth ◽  
Pulsed Laser ◽  
Complex Oxide ◽  
Laser Deposition ◽  
Layer By Layer ◽  
Interface Magnetism ◽  
Tunable Capacitors

In this chapter we will describe a new development of combinatorial pulsed laser deposition (CPLD) which targets the exploration of interface libraries. The idea is to modulate continuously the composition of interfaces on a few atomic layers in order to alter their functional properties. This unique combinatorial synthesis of interfaces is possible due to very specific PLD characteristics. The first one is its well-known ability for complex oxide stoichiometry transfer from the target to the film. The second one is the layer by layer control of thin film growth at the atomic level using in-situ RHEED characterization. The third one relates to the directionality of the ablated plume which allows for selective area deposition on the substrate using a mobile shadow-mask. However PLD also has some limitations and important PLD aspects to be considered for reliable CPLD are reviewed. Multiple examples regarding the control of interface magnetism in magnetic tunnel junctions and energy band and Schottky barrier height tuning in ferroelectric tunable capacitors are presented.

In Situ Spectroscopic Approach to Atomic Layer Deposition

2002 ◽  
Vol 745 ◽  
Author(s):  
Martin M. Frank ◽  
Yves J. Chabal ◽  
Glen D. Wilk
Keyword(s):  
Infrared Spectroscopy ◽  
Atomic Layer Deposition ◽  
Aluminum Oxide ◽  
Atomic Layer ◽  
Gate Oxide ◽  
Silicon Surfaces ◽  
Oxide Growth ◽  
Layer By Layer ◽  
Layer Deposition

ABSTRACTThere is great need for a mechanistic understanding of growth chemistry during atomic layer deposition (ALD) of films for electronic applications. Since commercial ALD reactors are presently not equipped for in situ spectroscopy, we have constructed a model reactor that enables single-pass transmission infrared spectroscopy to be performed in situ on a layer-by-layer basis. We demonstrate the viability of this approach for the study of aluminum oxide growth on silicon surfaces, motivated by alternative gate oxide applications. Thanks to submonolayer dielectric and adsorbate sensitivity, we can quantify oxide thicknesses and hydroxyl areal densities on thermal and chemical SiO2/Si(100) substrates. Methyl formation and hydroxyl consumption upon initial trimethylaluminum (TMA) reaction can also be followed. We verify that in situ grown Al2O3 films are compatible in structure to films grown in a commercial ALD reactor.

Formation of Ultra Smooth Bi-Based Ferroelectric Films and their size effect on Dielectric Constant

1997 ◽  
Vol 493 ◽  
Author(s):  
H. Tabata ◽  
T. Yanagita ◽  
M. Hamada ◽  
T. Kawai
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Coercive Field ◽  
Smooth Surface ◽  
Remanent Polarization ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Gate Bias ◽  
Deposition Technique ◽  
Ferroelectric Films

ABSTACTWe have formed Bi-based ferroelectric films, such as Bi2WO6, Bi2VO5.5(n=1), Bi2SrTa2O9, Bi3TiNbO9(n=2) and Bi4Ti3O12(n=3) using a pulsed laser deposition technique. Especially, the Bi2VO5.5 film shows an atomically smooth surface with a flat 2000-3000Å wide terrace and steps of 8 Å and 16Å which correspond to a half and one unit cell, respectively. The dielectric constant, remanent polarization and coercive field of the Bi2VO5.5 thin films formed on Nb-SrTiO3(100) are 8, 3.0 μ C/cm2 and 16.0 kV/cm, respectively. The Bi2VO5.5 film formed on SiO2/Si(100) shows memory windows of 0.35V against a±2V gate bias during C-V measurements‥

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