scholarly journals On the origin of in-gap states in homogeneously disordered ultrathin films. MoC case

2018 ◽  
Vol 461 ◽  
pp. 143-148 ◽  
Author(s):  
V. Hašková ◽  
M. Kopčík ◽  
P. Szabó ◽  
T. Samuely ◽  
J. Kačmarčík ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Gap States

Epitaxial growth manner and structure of superconducting oxide films

1990 ◽  
Vol 48 (4) ◽  
pp. 2-3
Author(s):  
Yoshichika Bando ◽  
Takahito Terashima ◽  
Kenji Iijima ◽  
Kazunuki Yamamoto ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Film Surface ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Initial Growth ◽  
In Situ Growth ◽  
High Quality ◽  
Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

scholarly journals Scanning Thermal Microscopy of Ultrathin Films: Numerical Studies Regarding Cantilever Displacement, Thermal Contact Areas, Heat Fluxes, and Heat Distribution

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 491
Author(s):  
Christoph Metzke ◽  
Fabian Kühnel ◽  
Jonas Weber ◽  
Günther Benstetter
Keyword(s):  
Thermal Properties ◽  
Ultrathin Films ◽  
Hexagonal Boron Nitride ◽  
Thermal Contact ◽  
Heat Transfer Process ◽  
Heat Propagation ◽  
Heat Fluxes ◽  
Detailed Knowledge ◽  
Scanning Thermal Microscopy ◽  
Thermal Microscopy

New micro- and nanoscale devices require electrically isolating materials with specific thermal properties. One option to characterize these thermal properties is the atomic force microscopy (AFM)-based scanning thermal microscopy (SThM) technique. It enables qualitative mapping of local thermal conductivities of ultrathin films. To fully understand and correctly interpret the results of practical SThM measurements, it is essential to have detailed knowledge about the heat transfer process between the probe and the sample. However, little can be found in the literature so far. Therefore, this work focuses on theoretical SThM studies of ultrathin films with anisotropic thermal properties such as hexagonal boron nitride (h-BN) and compares the results with a bulk silicon (Si) sample. Energy fluxes from the probe to the sample between 0.6 µW and 126.8 µW are found for different cases with a tip radius of approximately 300 nm. A present thermal interface resistance (TIR) between bulk Si and ultrathin h-BN on top can fully suppress a further heat penetration. The time until heat propagation within the sample is stationary is found to be below 1 µs, which may justify higher tip velocities in practical SThM investigations of up to 20 µms−1. It is also demonstrated that there is almost no influence of convection and radiation, whereas a possible TIR between probe and sample must be considered.

scholarly journals Solvent-exchange process in MOF ultrathin films and its effect on CO2 and methanol adsorption

2021 ◽  
Vol 590 ◽  
pp. 72-81
Author(s):  
M.A. Andrés ◽  
P. Fontaine ◽  
M. Goldmann ◽  
C. Serre ◽  
O. Roubeau ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Exchange Process ◽  
Solvent Exchange ◽  
Methanol Adsorption

scholarly journals Deposition of Extended Ordered Ultrathin Films of Au 38 (SC 2 H 4 Ph) 24 Nanocluster using Langmuir–Blodgett Technique

Small ◽  
2021 ◽  
pp. 2005954
Author(s):  
Michal Swierczewski ◽  
Plinio Maroni ◽  
Alexis Chenneviere ◽  
Mohammad M. Dadras ◽  
Lay‐Theng Lee ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Langmuir Blodgett

scholarly journals Defect Processes in Halogen Doped SnO2

2021 ◽  
Vol 11 (2) ◽  
pp. 551
Author(s):  
Petros-Panagis Filippatos ◽  
Nikolaos Kelaidis ◽  
Maria Vasilopoulou ◽  
Dimitris Davazoglou ◽  
Alexander Chroneos
Keyword(s):  
Electronic Properties ◽  
Tin Oxide ◽  
Density Functional ◽  
Structural Changes ◽  
High Dielectric Constant ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Optical And Electronic Properties ◽  
High Dielectric ◽  
Gap States

In the present study, we performed density functional theory calculations (DFT) to investigate structural changes and their impact on the electronic properties in halogen (F, Cl, Br, and I) doped tin oxide (SnO2). We performed calculations for atoms intercalated either at interstitial or substitutional positions and then calculated the electronic structure and the optical properties of the doped SnO2. In all cases, a reduction in the bandgap value was evident, while gap states were also formed. Furthermore, when we insert these dopants in interstitial and substitutional positions, they all constitute a single acceptor and donor, respectively. This can also be seen in the density of states through the formation of gap states just above the valence band or below the conduction band, respectively. These gap states may contribute to significant changes in the optical and electronic properties of SnO2, thus affecting the metal oxide’s suitability for photovoltaics and photocatalytic devices. In particular, we found that iodine (I) doping of SnO2 induces a high dielectric constant while also reducing the oxide’s bandgap, making it more efficient for light-harvesting applications.

scholarly journals The Influence Mechanism of Temperature and Storage Period on Polarization Properties of Poly (Vinylidene Fluoride–Trifluoroethylene) Ultrathin Films

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 301
Author(s):  
Xingjia Li ◽  
Zhi Shi ◽  
Xiuli Zhang ◽  
Xiangjian Meng ◽  
Zhiqiang Huang ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Remanent Polarization ◽  
Vinylidene Fluoride ◽  
Storage Period ◽  
Testing Temperature ◽  
Fatigue Properties ◽  
Inhibition Mechanism ◽  
Poly Vinylidene Fluoride ◽  
High Level ◽  
And Storage

The effect of testing temperature and storage period on the polarization fatigue properties of poly (vinylidene fluoride-trifluoroethylene) (P(VDF–TrFE)) ultrathin film devices were investigated. The experimental results show that, even after stored in air for 150 days, the relative remanent polarization (Pr/Pr(0)) of P(VDF–TrFE) of ultrathin films can keep at a relatively high level of 0.80 at 25 °C and 0.70 at 60 °C. To account for this result, a hydrogen fluoride (HF) formation inhibition mechanism was proposed, which correlated the testing temperature and the storage period with the microstructure of P(VDF–TrFE) molecular chain. Moreover, a theoretical model was constructed to describe the polarization fatigue evolution of P(VDF–TrFE) samples.

scholarly journals Electrical conduction and photoconduction in PtSe2 ultrathin films

2020 ◽  
Author(s):  
Antonio Di Bartolomeo ◽  
Francesca Urban ◽  
Enver Faella ◽  
Alessandro Grillo ◽  
Aniello Pelella ◽  
...  
Keyword(s):  
Electrical Conduction ◽  
Ultrathin Films

scholarly journals Spin‐Crossover Molecules on Surfaces: From Isolated Molecules to Ultrathin Films

2021 ◽  
pp. 2008141
Author(s):  
Lalminthang Kipgen ◽  
Matthias Bernien ◽  
Felix Tuczek ◽  
Wolfgang Kuch
Keyword(s):  
Ultrathin Films ◽  
Spin Crossover ◽  
Isolated Molecules
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