Improved Growth Of Srga2s4 Thin Film Electroluminescence Phosphors

1996 ◽  
Vol 424 ◽  
Author(s):  
D. Braunger ◽  
T. A. Oberacker ◽  
U. Troppenz ◽  
H.-W. Schock
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
The Other ◽  
Crystal Quality ◽  
Cerium Chloride ◽  
Wave Excitation ◽  
Color Coordinates ◽  
Square Wave ◽  
True Blue ◽  
Source Materials

AbstractCerium activated ternary strontium thiogallate phosphor thin films have been deposited by multi-source evaporation of elemental strontium, gallium and sulfur as source materials. Cerium chloride (CeCI3) has been used as activator starting material. In order to avoid SrS as well as Ga phase segregations elemental In as well as compounds, such as LiF, NaF, LiCl, and SrCI2, have been investigated as possible growth enhancing agents.Coevaporation of indium resulted in an improved crystallization with the drawback of an increased reabsorption of the cerium emission. The other additives lead to improved crystal quality combined with true-blue cathodoluminescence (CL) performance (C.I.E. color coordinates of up to 0. 14/0.12) which proves phosphor layers without any SrS phase segregations.Thin film electroluminescent (TFEL) devices with SrGa2S4:CeCl3 phosphor layers prepared with LiF as additive exhibit highest ever reported L40 luminances of 78 cd/m2 and luminous efficiencies of 0.017 lm/W at a transferred charge of 1 μ;C/cm2 with 1 kHz / 50 μs bipolar square wave excitation.

Study on preparing PLT(28) thin film and its electro-optic effect

1998 ◽  
Vol 13 (5) ◽  
pp. 1266-1270 ◽  
Author(s):  
Ai-Li Ding ◽  
Wei-Gen Luo ◽  
P. S. Qiu ◽  
J. W. Feng ◽  
R. T. Zhang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetron Sputtering ◽  
Faraday Effect ◽  
The Other ◽  
Ceramic Powders ◽  
Glass Substrates ◽  
Annealing Conditions ◽  
Electro Optic

PLT(28) thin films deposited on glass substrates were studied by two sputtering processes. One is an in situ magnetron sputtering and the other is a low-temperature magnetron sputtering. The sintered PLT ceramic powders are used as a sputtering target for both processes. The influences of sputtering and annealing conditions on structure and crystallinity of the films were investigated. The electro-optic (E-O) properties of PLT(28) thin films prepared by the two processes were determined by a technique according to Faraday effect. The researches showed the E-O properties were strongly affected by the sputtering process. The film with larger grains exhibits stronger E-O effect. The quadratic E-O coefficient of PLT(28) thin film varies in the range of 0.1 × 10−16 to 1.0 × 10−16 (m/v)2.

scholarly journals Disconnecting structure and dynamics in glassy thin films

2017 ◽  
Vol 114 (40) ◽  
pp. 10601-10605 ◽  
Author(s):  
Daniel M. Sussman ◽  
Samuel S. Schoenholz ◽  
Ekin D. Cubuk ◽  
Andrea J. Liu
Keyword(s):  
Thin Film ◽  
Machine Learning ◽  
Thin Films ◽  
Predictive Models ◽  
Local Structure ◽  
The Other ◽  
Microscopic Structure ◽  
Glassy Dynamics ◽  
Structure And Dynamics ◽  
Machine Learning Methods

Nanometrically thin glassy films depart strikingly from the behavior of their bulk counterparts. We investigate whether the dynamical differences between a bulk and thin film polymeric glass former can be understood by differences in local microscopic structure. Machine learning methods have shown that local structure can serve as the foundation for successful, predictive models of particle rearrangement dynamics in bulk systems. By contrast, in thin glassy films, we find that particles at the center of the film and those near the surface are structurally indistinguishable despite exhibiting very different dynamics. Next, we show that structure-independent processes, already present in bulk systems and demonstrably different from simple facilitated dynamics, are crucial for understanding glassy dynamics in thin films. Our analysis suggests a picture of glassy dynamics in which two dynamical processes coexist, with relative strengths that depend on the distance from an interface. One of these processes depends on local structure and is unchanged throughout most of the film, while the other is purely Arrhenius, does not depend on local structure, and is strongly enhanced near the free surface of a film.

Optical and electrical properties of Ge10+xSe40Te50−x thin film

2001 ◽  
Vol 16 (6) ◽  
pp. 1549-1553 ◽  
Author(s):  
S. A. Fayek ◽  
M. El-Ocker ◽  
A. S. Hassanien
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Band Gap ◽  
The Other ◽  
Electrical Activation ◽  
Optical And Electrical Properties ◽  
Vacuum Deposition ◽  
Band Tail ◽  
Reflection And Transmission ◽  
Opposite Behavior

Thin films with thickness 100 nm of Ge10+xSe40Te50−x (x ranging from 0.0 to 16.65 at.%) were formed by vacuum deposition at 1.33 × 10−4 Pa. The change in electrical resistivity of the films has been measured using the coplanar method. The measurements have been carried out in a temperature range between 400 and 142 K. The values of the electrical activation energies lie in the range of 0.18–0.38 eV. The optical absorption behavior of these ternary thin films was studied from the reflection and transmission. The optical band gap was found to be in the range of 0.90–1.11 eV and arose from indirect transitions. On the other hand, the width of the band tail Ee was found in the range 0.19–0.32 eV and exhibits opposite behavior. This behavior is believed to be associated with a defected bond of Te–Te and a cohesive energy (CE).

Niobium and zirconium telluride thin films prepared by sputtering

1999 ◽  
Vol 14 (5) ◽  
pp. 2070-2079 ◽  
Author(s):  
Daniel Pailharey ◽  
Yves Mathey ◽  
Mohamad Kassem
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Substrate Temperature ◽  
Large Range ◽  
Sputter Deposition ◽  
The Other ◽  
Striking Feature ◽  
Structural Types ◽  
The One ◽  
Film Form

A versatile procedure of sputter deposition, well-adapted for getting a large range of Te/M ratios (with M = Zr or Nb), has led to the synthesis of several highly anisotropic zirconium and niobium polytellurides in thin film form. Upon tuning the two key parameters of the process, i.e., the Te percentage in the target and the substrate temperature during the deposition, preparation of systems ranging from ZrTe0.72 to ZrTe6.7, on the one hand, and from NbTe1.28 to NbTe7.84, on the other, has been achieved. Besides their amorphous or crystalline (with or without preferential orientations) behavior and their relationship to known structural types, the most striking feature of these films is their large departure from the stoichiometry of the bulk MTex reference compounds. This peculiarity, together with the possible changes of composition under annealing, are described and interpreted in terms of variable amounts of Te and M atoms trapped or intercalated within the parent structures.

Micro Texture Dependence of Both the Mechanical and Electrical Properties of Electroplated Copper Thin Films Used for Interconnection

2010 ◽  
Author(s):  
Naokazu Murata ◽  
Naoki Saito ◽  
Kinji Tamakawa ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Grain Boundaries ◽  
Fracture Mode ◽  
The Other ◽  
Copper Films ◽  
Mechanical And Electrical Properties ◽  
Electroplated Copper

Both mechanical and electrical properties of electroplated copper thin films were investigated experimentally with respect to changes in their micro texture. Clear recrystallization was observed after the annealing even at low temperature of about 150°C. The fracture strain of the film annealed at 400°C increased from the initial value of about 3% to 15%, and at the same time, the yield stress of the annealed film decreased from about 270 MPa to 90 MPa. In addition, it was found that there were two fatigue fracture modes in the film annealed at the temperatures lower than 200°C. One was a typical ductile fracture mode with plastic deformation and the other was brittle one. When the brittle fracture occurred, the crack propagated along weak or porous grain boundaries which remained in the film after electroplating. The brittle fracture mode disappeared after the annealing at 400°C. These results clearly indicated that the mechanical properties of electroplated copper thin films vary drastically depending on their micro texture. Next, the electrical reliability of electroplated copper thin film interconnections was discussed. The interconnections used for electromigration (EM) tests were made by damascene process. The width of the interconnections was varied from 1 μm to 10 μm. An abrupt fracture mode due to local fusion appeared in the as-electroplated films within a few hours during the test. Since the fracture rate increased linearly with the increase of square of the applied current density, this fracture mode was dominated by local Joule heating. It seemed that the local resistance of the film increased due to the porous grain boundaries and thus, the local temperature around the porous grain boundaries increased drastically. On the other hand, the life of the interconnections annealed at 400°C was improved significantly. This was because of the increase of the average grain size and the improvement of the quality of grain boundaries in the annealed films. The electrical properties of the electroplated copper films were also dominated by their micro texture. However, the stress migration occurred in the interconnections after the annealing at 400°C. This was because of the high residual tensile stress caused by the constraint of the densification of the films by the surrounding oxide film in the interconnection structures during the annealing. Finally, electroplating condition was controlled to improve the electrical properties. Both the resistance of electromigration and electrical resistivity were improved significantly. However, electromigration of copper atoms still occurred at the interface between the electroplated copper and the thin tantalum (Ta) layer sputtered as base material. Therefore, it is very important to control the crystallographic quality of electroplated copper films and the interface between different materials for improving the reliability of thin film interconnections.

Crystal Quality Improvement of CuInS2 Thin Film by Two Step Fabrication Method with Bismuth Addition

2013 ◽  
Vol 372 ◽  
pp. 563-566
Author(s):  
Shohei Fukamizu ◽  
Daisuke Hironiwa ◽  
Takashi Minemoto
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Size ◽  
Crystal Growth ◽  
Film Thickness ◽  
High Efficiency ◽  
Growth Promotion ◽  
Crystal Quality ◽  
Chemical Doping ◽  
Bi Doping

CuInS2 (CIS) is the promising candidate of an absorber layer of high efficiency thin film solar cells. The crystal quality of CIS is one of the important factors for high efficiency. A chemical doping approach using antimony and bismuth (Bi) is well known for improving crystal quality in Cu (In,Ga)Se2 thin films. In this study, the effect of Bi doping on evaporated CIS thin films was investigated. A CIS thin film without Bi doping annealed at 600°C showed small crystal grain size of ~1 μm, which was smaller than the CIS film thickness of 2 μm. The small addition of 50 nm-thick Bi promoted crystal growth and large grain size of greater than 1 μm, which was comparable to the CIS film thickness, was realized. The CIS films without and with Bi addition had surface precipitates identified as Cu-S and Cu-Bi-S compounds, respectively. The crystal growth promotion by Bi addition can be attributed to that the Cu-Bi-S compound which has lower melting point of 470~490°C than that of the Cu-S compound of 507°C acted as flux for crystal growth.

An Interesting Result of Dielectric Property for Novel Polyimides with Fluorene Groups

2010 ◽  
Vol 663-665 ◽  
pp. 511-514 ◽  
Author(s):  
Yuan Yuan ◽  
Bing Xie ◽  
Yu Wang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Dielectric Property ◽  
Dielectric Constants ◽  
The Other ◽  
Polyimide Films ◽  
Low Dielectric ◽  
High Dielectric ◽  
Biphenyltetracarboxylic Dianhydride

A series of polyimide thin films were prepared successfully based on bis[3,5-dimethyl-4- (4-aminophenoxy)phenyl]methane （BDAPM）, 9,9-bis（4-（4-aminophenoxy）phenyl）fluorene (BAOFL) and different dianhydrides. And an interesting result of dielectric property for polyimide thin films was found that the polyimide thin film prepared with 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) exhibited high dielectric constants of 5.7 at 1MHz. Conversely, the other polyimides possessing fluorene groups showed low dielectric constants. The structures and the mechanical properties of polyimide films also proved the reason for results of dielectric properties.

Ferroelectricity of BiFeO3 Thin Films by Pulsed Laser Deposition and Effect of Atmosphere

2006 ◽  
Vol 320 ◽  
pp. 45-48
Author(s):  
Hyun Young Go ◽  
Naoki Wakiya ◽  
Keisuke Satoh ◽  
Masao Kondo ◽  
Jeffrey S. Cross ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Roughness ◽  
Pulsed Laser Deposition ◽  
Epitaxial Film ◽  
Pulsed Laser ◽  
The Other ◽  
Laser Deposition ◽  
Phase Pure ◽  
Hysteresis Properties

In this study, BiFeO3 (BFO) epitaxial film was deposited on SrRuO3 (100)/SrTiO3 (100) substrates using pulsed laser deposition (PLD). Phase pure BFO thin film was obtained. Introducing a mask between the target and substrate in PLD improved the surface roughness from 47.8 nm (RMS, without mask) to 7.7 nm (RMS, with mask). The composition and electrical properties of BFO thin film were assessed after annealing for 1 h in Ar, N2, or O2 atmosphere at 600°C. The P-E hysteresis properties improved only in the O2 atmosphere. After annealing under O2 atmosphere, the leakage current decreased from 6.1 × 10-2 A/cm to 2.9 × 10-2 A/cm at 200 kV/cm, as in the other annealing atmospheres, but 2Pr increased from 35 BC/cm2 to 50 BC/cm2.

scholarly journals MnBi2Se4-Based Magnetic Modulated Heterostructures

Magnetism ◽  
2022 ◽  
Vol 2 (1) ◽  
pp. 1-9
Author(s):  
Evgeniy K. Petrov ◽  
Vladimir M. Kuznetsov ◽  
Sergey V. Eremeev
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
First Principles ◽  
Molecular Beam ◽  
Magnetoelectric Effect ◽  
Film Surface ◽  
Anomalous Hall Effect ◽  
The Other ◽  
First Principles Calculations ◽  
Magnetic Doping

Thin films of magnetic topological insulators (TIs) are expected to exhibit a quantized anomalous Hall effect when the magnetizations on the top and bottom surfaces are parallel and a quantized topological magnetoelectric effect when the magnetizations have opposite orientations. Progress in the observation of these quantum effects was achieved earlier in the films with modulated magnetic doping. On the other hand, the molecular-beam-epitaxy technique allowing the growth of stoichiometric magnetic van der Waals blocks in combination with blocks of topological insulator was developed. This approach should allow the construction of modulated heterostructures with the desired architecture. In the present paper, based on the first-principles calculations, we study the electronic structure of symmetric thin film heterostructures composed of magnetic MnBi2Se4 blocks (septuple layers, SLs) and blocks of Bi2Se3 TI (quintuple layers, QLs) in dependence on the depth of the magnetic SLs relative to the film surface and the TI spacer between them. Among considered heterostructures we have revealed those characterized by nontrivial band topology.

scholarly journals Ammonia Room Temperature Gas Sensor Using Different TiO2 Nano-structure

2021 ◽  
Author(s):  
Mostafa Shooshtari ◽  
Alireza Salehi
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Room Temperature ◽  
Operating Temperature ◽  
Anatase Phase ◽  
Fold Increase ◽  
The Other ◽  
Nano Structure ◽  
Two Samples ◽  
Quartz Glasses

Abstract In this study, TiO2 Nano-structure were synthesized by three different processes including nanowires, nanoparticles and thin- films. The morphology and crystal structure of the three different TiO2 structures deposited on quartz glasses were characterized by XRD, SEM and FTIR. It has been found that nanowires and nanoparticles showed only the anatase phase while the thin-film exhibited both anatase and rutile phases. The three TiO2 Nano-structures were then used to fabricate gas sensors for ammonia (NH3) detection at different concentrations and various conditions. The samples fabricated with thin-film TiO2 towards 50 ppm NH3 showed a response value of 5% at room temperature, whereas the other two samples exhibited much higher values towards similar condition NH3 at room temperature. Samples with nanowires showed a three-fold increase and samples with nanoparticles exhibit a two-fold increase in response value. We have found that the response of all samples increases with elevating the operating temperature up to 200°C. Increasing the operating temperature improved the nanoparticle sensing conditions more than the other two samples. The samples using nanoparticles showed a 33% increase in response towards 50 ppm NH3 at 200°C compared to the samples with thin films at similar conditions. Further, response and recovery time were investigated and reported in this study.

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