Search results for "Laser deposition"
showing 10 items of 80 documents
ITO top-electrodes via industrial-scale PLD for efficient buffer-layer-free semitransparent perovskite solar cells
2022
The deposition of transparent conductive oxides (TCO) usually employs harsh conditions that are frequently harmful to soft/organic underlayers. Herein, successful use of an industrial pulsed laser deposition (PLD) tool to directly deposit indium tin oxide (ITO) films on semitransparent vacuum-deposited perovskite solar cells without damage to the device stack is demonstrated. The morphological, electronic, and optical properties of the PLD deposited ITO films are optimized. A direct relation between the PLD chamber pressure and the solar cell performance is obtained. The semitransparent perovskite solar cells prepared exclusively by vacuum-assisted techniques had fill factors of 78% and exc…
Highly Homogeneous 2D/3D Heterojunction Diodes by Pulsed Laser Deposition of MoS2 on Ion Implantation Doped 4H-SiC
2022
In this paper, 2D/3D heterojunction diodes have been fabricated by pulsed laser deposition (PLD) of MoS2 on 4H-SiC(0001) surfaces with different doping levels, i.e., n− epitaxial doping (≈1016 cm−3) and n+ ion implantation doping (>1019 cm−3). After assessing the excellent thickness uniformity (≈3L-MoS2) and conformal coverage of the PLD-grown films by Raman mapping and transmission electron microscopy, the current injection across the heterojunctions is investigated by temperature-dependent current–voltage characterization of the diodes and by nanoscale current mapping with conductive atomic force microscopy. A wide tunability of the transport properties is shown by the SiC surface dopi…
Mechanical properties of nanostructured carbon layers grown by CVD and PLD techniques
2010
Pulsed laser deposition (PLD) and chemical vapour deposition (CVD) have been proven to be among the most successful techniques for growing the entire spectrum of carbon films, which can be used in a wide range of technical applications. Here an investigation has been performed to explore the effect of different growing techniques (PLD and CVD) and process parameters (such as deposition time and substrate type) on the films' morphology and mechanical properties. The mechanical properties of the grown thin films were characterised by means of nano/micro indentation and scratch test techniques. It was observed that the thickness of the Al2O3 interlayer (between the Fe catalyst nanoparticles an…
Comparison of LIBS results on ITER-relevant samples obtained by nanosecond and picosecond lasers
2019
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Work performed under EUROfusion WP PFC.
Stability/Instability of Conductivity and Work Function Changes of ITO Thin Films, UV-Irradiated in Air or Vacuum. Measurements by the Four-Probe Met…
2001
This study shows that, after UV-irradiation in air or vacuum, conductivity and work function of ITO and In2O3 come back to their initial values in a few hours or minutes. In addition to this instability, one of the reported drawbacks of ITO is the indium diffusion into the organic layers of operating LED, leading to performance degradation. So, we have reconsidered ITO as transparent anode and explored alternatives such as NiO.
Structure and properties of epitaxial ferroelectric PbLu0.5Nb0.5O3thin films
2001
Abstract Epitaxial thin film heterostructures of PbLu0.5Nb0.5O3 (PLuN) and La0.5Sr0.5CoO3 (LSCO) were deposited by in situ pulsed laser ablation onto MgO and LaAlO3 (100) substrates. The formation of crystalline phases, epitaxy, film-electrode-substrate orientation relationships, crystal perfection and chemical order were studied by x-ray diffraction. The structural properties were found to depend on the deposition conditions and on the substrate. The perovskite PLuN films were pseudocubic and epitaxial, with (001) planes parallel to the substrate surface. At room temperature, Au/PLuN/LSCO capacitors exhibited ferroelectric behavior and zero-field dielectric permittivity about e ≅ 210–260, …
Compositional Evolution of Properties in Epitaxial Films of Relaxor PbMg1/3Nb2/3O3-PbTiO3
2005
Epitaxial heterostructures of relaxor (1− x) PbMg1/3Nb2/3O3−(x) PbTiO3 thin films with La0.5Sr0.5CoO3 bottom electrodes were grown by pulsed laser ablation on MgO substrates. Perovskite films with x = 0–0.32 were deposited using sub-monolayer mixing from two targets. Both the room-temperature studies of microstructure and studies of dielectric response as a function of frequency and temperature were performed. For all x, a relaxor-like behavior was observed. The compositional evolution of lattice parameter, permittivity, and temperature of dielectric maxima T m was in a qualitative agreement with that in bulk. The relatively low temperatures T m in the presence of an in-plane compression we…
Some New Ceramics and Thin Films of Pb(B 3+ ,Nb)TiO 3 -PbTiO 3 System
2002
The structure, dielectric, and electromechanical properties of (1-x)Pb(B 3+ ,Nb)TiO 3 -xPbTiO 3 binary systems (B=Lu,Er,To,Ho) are reported. High values of the electromechanical coupling coefficien...
Oxide or carbide nanoparticles synthesized by laser ablation of a bulk Hf target in liquids and their structural, optical, and dielectric properties
2016
International audience; Laser ablation of a bulk Hf target in deionized (DI) water, ethanol, or toluene was carried out for the production of nanoparticles' colloidal solutions. Due to the interaction of the ablation plasma plume species with the species which are produced by the liquid decomposition at the plume-liquid interface, hafnia (HfO2) nanoparticles are synthesized in DI water, hafnium carbide (HfC) nanoparticles in toluene, and a mixture of these in ethanol. The hafnia nanoparticles are in the monoclinic low temperature phase and in the tetragonal and fcc high temperature phases. Their size distribution follows log-normal function with a median diameter in the range of 4.3–5.3 nm.…
Pulsed laser deposition of relaxor ferroelectric films
1998
Heterostructures of perovskite relaxor ferroelectric (RFE) thin films onto La 0.5 Sr 0.5 CoO bottom electrode layers were grown by pulsed laser deposition on MgO(100) crystal substrates. The films were highly oriented, with (h00) planes parallel to the substrate surface, and demonstrated good dielectric and ferroelectric quality at room temperature. The studies of the dielectric properties of the films over the frequency range of 20 Hz....100 kHz and over the temperature range of 0...350°C revealed relaxor type behavior in the films. A diffuse ferroelectric phase transition and a shift of the maximum dielectric permittivity towards higher temperatures with increasing frequency were observed…