Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Pulsed laser deposited GeTe-rich GeTe-Sb2Te3 thin films.

ABSTRACT: Pulsed laser deposition technique was used for the fabrication of Ge-Te rich GeTe-Sb2Te3 (Ge6Sb2Te9, Ge8Sb2Te11, Ge10Sb2Te13, and Ge12Sb2Te15) amorphous thin films. To evaluate the influence of GeTe content in the deposited films on physico-chemical properties of the GST materials, scanning electron microscopy with energy-dispersive X-ray analysis, X-ray diffraction and reflectometry, atomic force microscopy, Raman scattering spectroscopy, optical reflectivity, and sheet resistance temperature dependences as well as variable angle spectroscopic ellipsometry measurements were used to characterize as-deposited (amorphous) and annealed (crystalline) layers. Upon crystallization, optical functions and electrical resistance of the films change drastically, leading to large optical and electrical contrast between amorphous and crystalline phases. Large changes of optical/electrical properties are accompanied by the variations of thickness, density, and roughness of the films due to crystallization. Reflectivity contrast as high as ~0.21 at 405 nm was calculated for Ge8Sb2Te11, Ge10Sb2Te13, and Ge12Sb2Te15 layers.

SUBMITTER: Bouska M

PROVIDER: S-EPMC4873812 | biostudies-other | 2016

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Interface control by homoepitaxial growth in pulsed laser deposited iron chalcogenide thin films.

Project description:Thin film growth of iron chalcogenides by pulsed laser deposition (PLD) is still a delicate issue in terms of simultaneous control of stoichiometry, texture, substrate/film interface properties, and superconducting properties. The high volatility of the constituents sharply limits optimal deposition temperatures to a narrow window and mainly challenges reproducibility for vacuum based methods. In this work we demonstrate the beneficial introduction of a semiconducting FeSe(1-x)Te(x) seed layer for subsequent homoepitaxial growth of superconducting FeSe(1-x)Te(x) thin film on MgO substrates. MgO is one of the most favorable substrates used in superconducting thin film applications, but the controlled growth of iron chalcogenide thin films on MgO has not yet been optimized and is the least understood. The large mismatch between the lattice constants of MgO and FeSe(1-x)Te(x) of about 11% results in thin films with a mixed texture, that prevents further accurate investigations of a correlation between structural and electrical properties of FeSe(1-x)Te(x). Here we present an effective way to significantly improve epitaxial growth of superconducting FeSe(1-x)Te(x) thin films with reproducible high critical temperatures (≥17 K) at reduced deposition temperatures (200 °C-320 °C) on MgO using PLD. This offers a broad scope of various applications.

| S-EPMC4637838 | biostudies-literature

Test-photostability of pulsed laser deposited amorphous thin films from Ge-As-Te system.

Project description:Amorphous thin films from Ge-As-Te system were prepared by pulsed laser deposition to study their intrinsic photostability, morphology, chemical composition, structure and optical properties. Photostability of fabricated layers was studied by spectroscopic ellipsometry within as-deposited as well as relaxed (annealed) layers. For irradiation, laser sources operating at three wavelengths in band gap region of the studied materials were employed. The results show that lowest values of photorefraction accompanied with lowest changes of band gap values were exhibited by Ge20As20Te60 thin films, which are therefore considered as the layers with highest photostability in relaxed state. The structure of the films is discussed based on Raman scattering spectroscopy data.

| S-EPMC4369751 | biostudies-other

Pulsed Laser Porosification of Silicon Thin Films.

Project description:We present a new and simple laser-based process to porosify thin film silicon using a pulsed laser. During deposition, we incorporate gas atoms or molecules into the Si thin film. Pulsed laser radiation of wavelength λ = 532 nm heats up thin film Si beyond its melting point. Upon heating, gas atoms or molecules form nm-sized thermally expanding gas bubbles in the silicon melt, until they explosively exit the film, leaving pores behind. Rapid heating and fast cooling during pulsed laser processing enable re-solidification of the liquid Si before the created pores contract and pore closure occurs within the liquid phase. Optimized plasma-enhanced chemical vapor deposition or sputtering of amorphous Si thin films on stainless steel substrate incorporates the necessary concentration of gas atoms or molecules. We are able to tailor the pore size between 50 and 550 nm by changing laser pulse energy density and film deposition parameters. Evaporated silicon containing no gas atoms forms only a few very large μ m-sized gas bubbles due to laser-induced vapor formation of evaporated solid material at the substrate-silicon interface.

| S-EPMC5456937 | biostudies-other

Electrical and Optical Properties of Nb-doped SrSnO3 Epitaxial Films Deposited by Pulsed Laser Deposition.

Project description:Nb-doped SrSnO3 (SSNO) thin films were epitaxially grown on LaAlO3(001) single-crystal substrates using pulsed laser deposition under various oxygen pressures and substrate temperatures. The crystalline structure, electrical, and optical properties of the films were investigated in detail. X-ray diffraction results show that the cell volume of the films reduces gradually with increasing oxygen pressure while preserving the epitaxial characteristic. X-ray photoelectron spectroscopy analysis confirms the Nb5+ oxidation state in the SSNO films. Hall-effect measurements were performed and the film prepared at 0.2 Pa with the 780 °C substrate temperature exhibits the lowest room-temperature resistivity of 31.3 mΩcm and Hall mobility of 3.31 cm2/Vs with a carrier concentration at 6.03 × 1019/cm3. Temperature-dependent resistivity of this sample displays metal-semiconductor transition and is explained mainly by electron-electron effects. Optical transparency of the films is more than 70% in the wavelength range from 600 to 1800 nm. The band gaps increase from 4.35 to 4.90 eV for the indirect gap and 4.82 to 5.29 eV for the direct by lowering oxygen pressure from 20 to 1 × 10-3 Pa, which can be interpreted by Burstein-Moss effect and oxygen vacancies generated in the high vacuum.

| S-EPMC7431481 | biostudies-literature

Tunable critical temperature for superconductivity in FeSe thin films by pulsed laser deposition.

Project description:Stabilized FeSe thin films in ambient pressure with tunable superconducting critical temperature would be a promising candidate for superconducting electronic devices. By carefully controlling the depositions on twelve kinds of substrates using a pulsed laser deposition technique single crystalline FeSe thin films were fabricated. The high quality of the thin films was confirmed by X-ray diffraction with a full width at half maximum of 0.515° in the rocking curve and clear four-fold symmetry in ?-scan. The films have a maximum T c ~ 15?K on the CaF2 substrate and were stable in ambient conditions air for more than half a year. Slightly tuning the stoichiometry of the FeSe targets, the superconducting critical temperature becomes adjustable below 15?K with quite narrow transition width less than 2?K. These FeSe thin films deposited on different substrates are optimized respectively. The Tc of these optimized films show a relation with the out-of-plane (c-axis) lattice parameter of the FeSe films.

| S-EPMC5840431 | biostudies-literature

Li-rich thin film cathode prepared by pulsed laser deposition.

Project description:Li-rich layer-structured cathode thin films are prepared by pulsed laser deposition. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscopy (XPS) and electrochemical testing in half battery cells are used to characterize crystal structure, surface morphology, chemical valence states and electrochemical performance of these thin films, respectively. It is observed that partial layer to spinel transformation takes place during post annealing, and the layered structure further gradually transforms to spinel during electrochemical cycling based on the analysis of dQ/dV. Electrochemical measurement shows that the thin film electrode deposited at 350 mTorr and post-annealed at 800 °C possesses the best performance.

| S-EPMC3840378 | biostudies-other

Combined magnetron sputtering and pulsed laser deposition of TiO 2 and BFCO thin films.

Project description:We report the successful demonstration of a hybrid system that combines pulsed laser deposition (PLD) and magnetron sputtering (MS) to deposit high quality thin films. The PLD and MS simultaneously use the same target, leading to an enhanced deposition rate. The performance of this technique is demonstrated through the deposition of titanium dioxide and bismuth-based perovskite oxide Bi2FeCrO6 (BFCO) thin films on Si(100) and LaAlO3 (LAO) (100). These specific oxides were chosen due to their functionalities, such as multiferroic and photovoltaic properties (BFCO) and photocatalysis (TiO2). We compare films deposited by conventional PLD, MS and PLD combined with MS, and show that under all conditions the latter technique offers an increased deposition rate (+50%) and produces films denser (+20%) than those produced by MS or PLD alone, and without the large clusters found in the PLD-deposited films. Under optimized conditions, the hybrid technique produces films that are two times smoother than either technique alone.

| S-EPMC5451404 | biostudies-literature

Ultra Uniform Pb0.865La0.09(Zr0.65Ti0.35)O? Thin Films with Tunable Optical Properties Fabricated via Pulsed Laser Deposition.

Project description:Ferroelectric thin films have been utilized in a wide range of electronic and optical applications, in which their morphologies and properties can be inherently tuned by a qualitative control during growth. In this work, we demonstrate the evolution of the Pb0.865La0.09(Zr0.65Ti0.35)O? (PLZT) thin films on MgO (200) with high uniformity and optimized optical property via the controls of the deposition temperatures and oxygen pressures. The perovskite phase can only be obtained at the deposition temperature above 700 °C and oxygen pressure over 50 Pa due to the improved crystallinity. Meanwhile, the surface morphologies gradually become smooth and compact owing to spontaneously increased nucleation sites with the elevated temperatures, and the crystallization of PLZT thin films also sensitively respond to the oxygen vacancies with the variation of oxygen pressures. Correspondingly, the refractive indices gradually develop with variations of the deposition temperatures and oxygen pressures resulted from the various slight loss, and the extinction coefficient for each sample is similarly near to zero due to the relatively smooth morphology. The resulting PLZT thin films exhibit the ferroelectricity, and the dielectric constant sensitively varies as a function of electric filed, which can be potentially applied in the electronic and optical applications.

| S-EPMC5951371 | biostudies-literature

Chemical Vapor Deposited Mixed Metal Halide Perovskite Thin Films.

Project description:In this article, we used a two-step chemical vapor deposition (CVD) method to synthesize methylammonium lead-tin triiodide perovskite films, MAPb1-xSnxI3, with x varying from 0 to 1. We successfully controlled the concentration of Sn in the perovskite films and used Rutherford backscattering spectroscopy (RBS) to quantify the composition of the precursor films for conversion into perovskite films. According to the RBS results, increasing the SnCl2 source amount in the reaction chamber translate into an increase in Sn concentration in the films. The crystal structure and the optical properties of perovskite films were examined by X-ray diffraction (XRD) and UV-Vis spectrometry. All the perovskite films depicted similar XRD patterns corresponding to a tetragonal structure with I4cm space group despite the precursor films having different crystal structures. The increasing concentration of Sn in the perovskite films linearly decreased the unit volume from about 988.4 Å3 for MAPbI3 to about 983.3 Å3 for MAPb0.39Sn0.61I3, which consequently influenced the optical properties of the films manifested by the decrease in energy bandgap (Eg) and an increase in the disorder in the band gap. The SEM micrographs depicted improvements in the grain size (0.3-1 µm) and surface coverage of the perovskite films compared with the precursor films.

| S-EPMC8269519 | biostudies-literature

Structural Properties of Thin ZnO Films Deposited by ALD under O-Rich and Zn-Rich Growth Conditions and Their Relationship with Electrical Parameters.

Project description:The structural, optical, and electrical properties of ZnO are intimately intertwined. In the present work, the structural and transport properties of 100 nm thick polycrystalline ZnO films obtained by atomic layer deposition (ALD) at a growth temperature (Tg) of 100-300 °C were investigated. The electrical properties of the films showed a dependence on the substrate (a-Al2O3 or Si (100)) and a high sensitivity to Tg, related to the deviation of the film stoichiometry as demonstrated by the RT-Hall effect. The average crystallite size increased from 20-30 nm for as grown samples to 80-100 nm after rapid thermal annealing, which affects carrier scattering. The ZnO layers deposited on silicon showed lower strain and dislocation density than on sapphire at the same Tg. The calculated half crystallite size (D/2) was higher than the Debye length (LD) for all as grown and annealed ZnO films, except for annealed ZnO/Si films grown within the ALD window (100-200 °C), indicating different homogeneity of charge carrier distribution for annealed ZnO/Si and ZnO/a-Al2O3 layers. For as grown films the hydrogen impurity concentration detected via secondary ion mass spectrometry (SIMS) was 1021 cm-3 and was decreased by two orders of magnitude after annealing, accompanied by a decrease in Urbach energy in the ZnO/a-Al2O3 layers.

| S-EPMC8307850 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data