Search results for "LM"

Impact of the molecular structure of an indandione fragment containing azobenzene derivatives on the morphology and electrical properties of thin fil…

2016

Abstract The solution casting method is low-cost processing method. Moreover, it is possible to prepare amorphous thin films by using this method, and thus, both optical quality and electrical properties could be improved in compare to polycrystalline films made by thermal evaporation in vacuum. Therefore, low-molecular-weight compounds that form amorphous structure from solution could be promising in organic electronics. In this work film morphology, molecule energy levels, and charge carrier mobility in thin films of indandione fragment containing azobenzene derivatives were studied. Deep charge carrier trapping states that drastically influenced charge carrier mobility were observed for …

Investigation of ZrO[sub 2]–Gd[sub 2]O[sub 3] Based High-k Materials as Capacitor Dielectrics

2010

Atomic layer deposition (ALD) of ZrO 2 ―Gd 2 O 3 nanolaminates and mixtures was investigated for the preparation of a high permittivity dielectric material. Variation in the relative number of ALD cycles for constituent oxides allowed one to obtain films with controlled composition. Pure ZrO 2 films possessed monoclinic and higher permittivity cubic or tetragonal phases, whereas the inclusion of Gd 2 O 3 resulted in the disappearance of the monoclinic phase. Changes in phase composition were accompanied with increased permittivity of mixtures and laminates with low Gd content. Further increase in the lower permittivity Gd 2 O 3 content above 3.4 cat. % resulted in the decreased permittivity…

Single crystal-like thin films of blue bronze

2021

Abstract Pulsed laser deposition technique was employed to grow thin films of K 0.3 M o O 3 on A l 2 O 3 (1-102) and S r T i O 3 (510) substrates. Structural and imaging characterization revealed good quality films with well oriented grains of few microns in length. Both non-selective (transport) and order-selective (femtosecond pump-probe spectroscopy) probes revealed charge density wave properties that are very close to those of the single crystals. The films exhibit metal-semiconductor phase transition in resistivity, pump-probe data show phase transition at the same temperature as the single crystal and the threshold for the photo-induced phase transition is approximately the same as in…

Correlation between in situ structural and optical characterization of the semiconductor-to-metal phase transition of VO2 thin films on sapphire

2020

A detailed structural investigation of the semiconductor-to-metal transition (SMT) in vanadium dioxide thin films deposited on sapphire substrates by pulsed laser deposition was performed by in situ temperature-dependent X-ray diffraction (XRD) measurements. The structural results are correlated with those of infrared radiometry measurements in the SWIR (2.5-5 μm) and LWIR (8-10.6 μm) spectral ranges. The main results indicate a good agreement between XRD and optical analysis, therefore demonstrating that the structural transition from monoclinic to tetragonal phases is the dominating mechanism for controlling the global properties of the SMT transition. The picture that emerges is a SMT tr…

2021

Atomic layer deposition (ALD) technology has unlocked new ways of manipulating the growth of inorganic materials. The fine control at the atomic level allowed by ALD technology creates the perfect conditions for the inclusion of new cationic or anionic elements of the already-known materials. Consequently, novel material characteristics may arise with new functions for applications. This is especially relevant for inorganic luminescent materials where slight changes in the vicinity of the luminescent centers may originate new emission properties. Here, we studied the luminescent properties of CaS:Eu by introducing europium with oxygen ions by ALD, resulting in a novel CaS:EuO thin film. We …

Electromagnetically induced switching of ferroelectric thin films

2007

We analyze the interaction of an electromagnetic spike (one cycle) with a thin layer of ferroelectric medium with two equilibrium states. The model is the set of Maxwell equations coupled to the undamped Landau-Khalatnikov equation, where we do not assume slowly varying envelopes. From linear-scattering theory, we show that low-amplitude pulses can be completely reflected by the medium. Large-amplitude pulses can switch the ferroelectric. Using numerical simulations and analysis, we study this switching for long and short pulses, estimate the switching times, and provide useful information for experiments.

Transport properties of Bi2Sr2Ca2Cu3O10+δ Bicrystal Grain Boundary Josephson Junctions and SQUIDs

1996

Josephson junctions and SQUIDs on 36.8° SrTiO 3 bicrystal substrates were prepared from epitaxial Bi 2 Sr 2 Ca 2 Cu 3 O 10+δ thin films with critical temperatures around 95K. The current-voltage characteristics are well described by the resistively and capacitively shunted junction model. I c R n products of 50μV at 77K and 0.7mV at 4.2K have been reached. The I c (B) dependence is symmetric to B = 0 with an I c suppression of 90% in the first minimum. Nevertheless it turns out, that the junctions are inhomogeneous on a μm scale. SQUID modulations observed at 78K indicate a flux-voltage transfer function of 2.7μV/Φ 0 at this temperature.

Accumulation of positrons from a LINAC based source

2020

International audience; The GBAR experiment aims to measure the gravitational acceleration of antihydrogen H̅. It will use H̅+ ions formed by the interaction of antiprotons with a dense positronium cloud, which will require about 1010 positrons to produce one H̅+. We present the first results on the positron accumulation, reaching 3.8±0.4×108 e+ collected in 560 s.

Simulation and optimization of the implantation of holmium atoms into metallic magnetic microcalorimeters for neutrino mass determination experiments

2017

Abstract Several novel experiments designed to investigate the electron neutrino mass in the sub-eV region are based on the calorimetric measurement of the 163Ho electron capture spectrum. For this the 163Ho source, with a required activity of the order of 1 to 100 Bq , needs to be enclosed in the detector, having a volume smaller than 10 − 3 mm 3 . Ion implantation is presently considered to be the most reliable method to enclose this source in the detector homogeneously distributed in a well defined volume. We have investigated the distribution of implanted holmium ions in different target materials and for different implantation energies by means of Monte Carlo simulations based on the S…

Interferences in Locally Resonant Sonic Metamaterials Formed from Helmholtz Resonators

2019

[EN] The emergence of materials artificially designed to control the transmission of waves, generally called metamaterials, has been a hot topic in the field of acoustics for several years. The design of these metamaterials is usually carried out by overlapping different wave control mechanisms. An example of this trend is the so-called Locally Resonant Sonic Materials, being one of them the Phononic Crystals with a local resonant structure. These metamaterials are formed by sets of isolated resonators in such a way that the control of the waves is carried out by resonances and by the existence of Bragg bandgaps, which appear due to the ordered distribution of the resonators. Their use is b…