A5011155607- solar cell performance optimization
- ZnO doping and properties
- Copper-based nanomaterials and applications
- Silicon and Solar Cell Technologies
- Chalcogenide Semiconductor Thin Films
- Semiconductor Quantum Structures and Devices
- Advanced Condensed Matter Physics
- Thin-Film Transistor Technologies
- GaN-based semiconductor devices and materials
- Electronic and Structural Properties of Oxides
- Ga2O3 and related materials
- Semiconductor materials and devices
- Nanowire Synthesis and Applications
- Photovoltaic System Optimization Techniques
- Gas Sensing Nanomaterials and Sensors
- Electron and X-Ray Spectroscopy Techniques
- Quantum Dots Synthesis And Properties
- Physics of Superconductivity and Magnetism
- Laser-induced spectroscopy and plasma
- Theoretical and Computational Physics
- Magnetic and transport properties of perovskites and related materials
- Multiferroics and related materials
- Advancements in Battery Materials
- Chemical Synthesis and Characterization
- Semiconductor materials and interfaces
Universidad Politécnica de Madrid
2011-2023
Universidad de Málaga
2010-2019
Material (Belgium)
2016
Laboratoire Mathématiques, Image et Applications
2016
Consejo Superior de Investigaciones Científicas
1997
Universidad de Zaragoza
1992-1995
Instituto de Nanociencia y Materiales de Aragón
1992-1995
Universidade de São Paulo
1992
A careful and wide comparison between Al Ga as substitutional dopants in the ZnO wurtzite structure is presented. Both cations behave n-type their inclusion improves optical electrical properties of matrix, making it more transparent visible range rising up its conductivity. However, same dopant/Zn ratio leads to a very different doping efficiency when comparing Ga, being cation effective dopant film. The measured differences Al- Ga-doped films are explained with hypothesis that quantities...
The refractive index and extinction coefficient of chemical vapour deposition grown graphene are determined by ellipsometry analysis. Graphene films were on copper substrates transferred as both monolayers bilayers onto SiO2/Si using standard manufacturing procedures. nature thickness residual debris formed after the transfer process elucidated photoelectron spectroscopy. real layered structure so deduced has been used instead nominal one input in analysis monolayer bilayer graphene, native...
Highly uniform films of pure electrodeposited in variable particle size (micronic and submicronic), morphology, thickness (0.3-13 μm) depending on the applied potential amount electrical charge transferred were examined as working electrodes lithium cells to check their suitability anodes for Li-ion cells. The thinnest film studied delivered a specific capacity close theoretical value; such decreased with increasing size. All except thickest exhibited excellent retention upon extensive...
Magnetite, goethite, and lepidocrocite thin films have been electrochemically grown on titanium substrates by the anodic oxidation of ferrous ions in a , pH 6.0, aqueous solution. It is demonstrated that deposition potential can be used as tool to tune obtainment different pure phases iron oxide-oxyhydroxides films. Results an exhaustive structural characterization, morphological study, X-ray photoelectron spectroscopy characterization are presented.
Copper(I) oxide (Cu2O) films were cathodically electrodeposited on titanium substrates. The influence of several electrodeposition parameters such as applied potential, pH, and bath temperature phase composition, degree crystallinity, grain size, orientation carefully examined using X-ray diffraction scanning electron microscopy. Two different surface morphologies with preferential crystal orientations are found at low (30 °C) pH 9 a function the potential. At same temperature, highly...
In previous works, the electrochemical deposition method has been used to prepare pure Cu2O films onto titanium substrates from an aqueous cupric lactate solution. Recently, they have shown react reversibly with Li. The phase composition, microstructure, and especially surface morphology, crystal or grain size, thickness of these can be varied by changing electrodeposition parameters. Because characteristics determine response toward Li+, a study their kinetics mechanisms nucleation growth...
We report on the correlation between electrical behavior and valence band spectra of undoped Al-doped ZnO films, obtained by using x-ray photoelectron spectroscopy. Although Al-doping can induce a conductivity increase two orders magnitude, we show that gap persists there is no semiconductor–metal transition upon doping. For 3% film, measure reduction in ∼150meV with respect to 1% doped films. Our results suggest conduction mechanism proposed for at room temperature still dominates process
Al- and Ga-doped sputtered ZnO films (AZO, GZO) are semiconducting metallic, respectively, despite the same electronic valence structure of dopants. Using hard X-ray photoelectron spectroscopy we observe that both dopants induce a band in near Fermi level, accompanied by narrowing Zn 3d/O 2p gap and, case GZO, substantial shift 3d. Ga occupies substitutional sites, whereas Al interstitial sites. The latter could O defects, which act as acceptors explaining character AZO lack variation...
Highly uniform electrodeposited Cu2O electrodes for Li-ion batteries, with variable particle size, morphology and thickness, have been studied in the charged discharged steps as a function of number cycling processes, by means ex situ X-ray absorption spectroscopy (XAS) at Cu K edge. Both, fingerprint analysis Absorption Near Edge Structure spectra (XANES) radial atomic distribution obtained Extended Fine (EXAFS) spectra, allowed us to quantify bimodal (Cu Cu2O) electrodes. These results...
After the feasibility of 1,3-dipolar cycloaddition reaction between nitrile imines and exfoliated graphene by density functional theory calculations was proved, very few-layer effectively functionalized using this procedure. Hydrazones with different electronic properties were used as precursors for 1,3-dipoles, microwave irradiation an energy source enabled to be performed in a few minutes. The anchoring organic addends on surface confirmed Raman spectroscopy, X-ray photoelectron...
We present a synchrotron radiation hard x-ray photoemission spectroscopy study of the electronic structure Al-doped ZnO films. Doping-induced states appear between Zn3$d$ and O2$p$ levels in band gap just below conduction minimum (CBM). Ab initio calculations confirm Al impurity origin these induced states. The drop film resistivity with doping is not due to progressive shifting Fermi level above CBM, but rather filling state, which pins CBM.
Abstract Accelerated life tests are frequently used to provide reliability information in a moderate period of time (weeks or months), and after that, failure analysis is compulsory detect the origins. In this paper, has been carried out temperature accelerated test on lattice matched GaInP/Ga(In)As/Ge triple junction commercial solar cells. Solar cells were forward biased darkness inside three climatic chambers order emulate photo‐generated current under nominal working conditions (a...
Abstract In this work, we demonstrate a new manufacturing process that allows to fabricate thin solar cells avoiding problems related the brittleness or fragility of wafers without needing any carrier nor temporary substrate. This technique has been successfully applied Ge single and GaInP/Ga(In)As/Ge triple‐junction grown on substrates, achieving 47.5‐ 55.5‐μm‐thick respectively. Although should allow substrates desired thickness, final thickness around 20–30 μm is recommended due practical...
MgF2, ZnS, Ta2O5, Al2O3 and TiO2 are some of the most common dielectric materials actually used in solar cells as anti-reflective coatings. For such purpose, they have been deposited by electron beam evaporation, which is one preferred technique industrial settings. In this work we aim to understand relationship between their optical physical properties deposition parameters thicknesses, being spectroscopic ellipsometry main for issue. MgF2 ZnS demonstrated rather good quality except...
Deviations of the Sedov-Taylor scaling at three different laser ablation regimes (500 mJ in a 0.8 mm spot, 50 spot and 500 2.5 spot) were investigated using Schlieren photography combination with optical scattering emission spectrometry, among others. For each case, time evolution shock front was related to formation, expansion properties plasma. Both, scale radiative processes that observed for vapor condensation into nanoparticles sub-micron particles are compatible divergences found...