A5103180839- Ga2O3 and related materials
- ZnO doping and properties
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Gas Sensing Nanomaterials and Sensors
- Advanced Chemical Sensor Technologies
- Spectroscopy and Laser Applications
- Advanced Photocatalysis Techniques
- Electronic and Structural Properties of Oxides
- Mechanical and Optical Resonators
- Phase-change materials and chalcogenides
- Chalcogenide Semiconductor Thin Films
- Nonlinear Optical Materials Studies
- Nanowire Synthesis and Applications
- thermodynamics and calorimetric analyses
- Atmospheric and Environmental Gas Dynamics
- Photonic and Optical Devices
- Phytochemistry and Bioactive Compounds
- Cytomegalovirus and herpesvirus research
- Advanced Fiber Laser Technologies
- Chemical and Physical Properties in Aqueous Solutions
- Tracheal and airway disorders
- Solid-state spectroscopy and crystallography
- Air Quality Monitoring and Forecasting
- Luminescence Properties of Advanced Materials
National Institute of Optics
2016-2024
Institute for Microelectronics and Microsystems
2020-2024
National Research Council
2020-2022
Universidad Complutense de Madrid
1994-2018
Hospital Universitario Virgen del Rocío
2014-2015
The influence of indium doping on morphology, structural, and luminescence properties gallium oxide micro- nanostructures is reported. Indium-doped have been grown by thermal oxidation metallic in the presence oxide. dominant morphologies are beltlike structures, which many cases twisted leading to springlike showing that In diffusion Ga2O3 influences microstructure shapes. High-resolution transmission electron microscopy has revealed twins belts, energy-dispersive X-ray spectroscopy...
Elongated micro- and nanostructures of Sn doped or Cr codoped monoclinic gallium oxide have been grown by a thermal method. The presence during growth has shown to strongly influence the morphology resulting structures, including branched wires, whips, needles. Subsequent codoping with is achieved through diffusion for photonic purposes. formation mechanism structures studied transmission electron microscopy (TEM). Epitaxial demonstrated in some cases, revealed very high quality interface...
The achievable sensitivity level of photo-acoustic trace-gas sensors essentially depends on the performances acoustic transducer. In this work, mechanical response different silicon-based micro-electro-mechanical systems (MEMS) is characterized, aiming at investigating both their properties, namely resonance frequency and quality factor, minimum detection limit (MDL) when they are exploited as an acoustic-to-voltage transducer in a photoacoustic setup. For purpose, 4.56 µm Continuous-Wave...
Abstract The behaviour of β -Ga 2 O 3 nanowires as photoconductive material in deep ultraviolet photodetectors to operate the energy range 3.0–6.2 eV has been investigated. were grown by a catalyst-free thermal evaporation method on gallium oxide substrates. Photocurrent measurements have carried out both undoped and Sn-doped Ga evidence influence dopant photodetector performances. responsivity spectrum single show maxima 4.8–5.4 strong dependence pulse frequency excitation light observed...
Enrichment of GeSbTe alloys with germanium has been proposed as a valid approach to increase the crystallization temperature and therefore address high-temperature applications non-volatile phase change memories, such embedded or automotive applications. However, tendency Ge-rich decompose segregation pure Ge still calls for investigations on basic mechanisms leading element diffusion compositional variations. With purpose identifying some possible routes limit segregation, in this study, we...
Crossed nanowire structures are the basis for high-density integration of a variety nanodevices. Owing to critical role nanowires intersections in creating hybrid architectures, it has become challenge investigate local structure crossing points metal oxide nanowires. Thus, if intentionally grown crossed well-patterned, an ideal model study junction is formed. By combining electron and synchrotron beam nanoprobes, we show here experimental evidence impurities coupling formation, structural...
The crystallization process of melt quenched Ge-rich GeSbTe films, with composition optimized for memory applications, has been studied by optical reflectance measurements. properties have related to the structure and means effective medium approximation. compositional variations investigated transmission electron microscopy energy loss spectroscopy. Amorphous materials prepared melt-quenching different laser densities studied. For density 1.5 J cm−2, a uniform amorphous layer, embedded Ge...
Gallium oxide microrods have been grown by an evaporation-deposition method using a precursor containing lithium in order to check the influence of such dopant on morphology and physical properties obtained s-Ga_2O_3 structures. SEM studies show that is modified with respect undoped gallium oxide, promoting growth micropyramids transversal microwire axis. Raman analysis reveals good crystal quality additional peak centred at around 270 cm^(-1), characteristic these samples not present...
Fabry Perot resonant modes in the optical range 660-770 nm have been detected from single and coupled Cr doped gallium oxide microwires at room temperature. The luminescence is due to chromium ions dominated by broad band involving T-4(2)-(4)A(2) transition, strongly phonons, which could be of interest tunable lasers. confinement emitted photons leads both ends wires. separation wavelength between maxima follows Fabry-Perot dependence on wire length group refractive index for Ga2O3 microwires.
In this study, we deposit a Ge-rich Ge–Sb–Te alloy by physical vapor deposition (PVD) in the amorphous phase on silicon substrates. We study in-situ, X-ray and ultraviolet photoemission spectroscopies (XPS UPS), electronic properties carefully ascertain composition to be GST 29 20 28. Subsequently, Raman spectroscopy is employed corroborate results from study. diffraction used upon annealing crystallization of such an identify effects separation segregation crystalline Ge with formation...
The coexistence curves of the system dodecylammonium chloride+water+KCl have been measured at different salt concentrations. results can be described with usual Ising 3-D value for critical exponent β=0.325. analysis diameter indicates that correct order parameter is defined in terms an effective concentration calculated according to Eq. (4). Both and curve point out range validity simple scaling decreases KCl concentration, i.e., as approaches a end point. line, estimation Krafft...
Abstract The field emission properties of gallium oxide nanowires grown by thermal evaporation–deposition have been investigated inside the chamber a scanning electron microscope. Turn on electric fields and enhancement factors determined for Sn doped nanowires. X‐ray photoelectron spectroscopy measurements performed to calculate work function Ga 2 O 3 . results show improved nanowires, with lower threshold (below 1.0 V/µm). obtained values are competitive those achieved in other...
Ga<sub>2</sub>O<sub>3</sub> bulk single crystals have been implanted with 300 keV Europium ions to fluences ranging from 1×10<sup>13</sup> 4×10<sup>15</sup> at/cm<sup>2</sup>. The damage build-up and Eu-incorporation was assessed by Rutherford Backscattering Spectrometry in the channeling mode (RBS/C). RBS/C results suggest that implantation causes a mixture of defect clusters extended defects such as dislocations. Amorphisation starts at surface for around...
High quality Zn‐doped monoclinic gallium oxide micro‐ and nanostructures are obtained by a thermal treatment based on vapor–solid (VS) growth mechanism. Nanowires ribbons formed, the latter being more abundant. The microstructural features assessed micro‐Raman transmission electron microscopy revealing their crystal structure properties, such as [‐110] direction for single crystals. In particular, strong‐scattered light polarization dependence is reflected in detected Raman modes....
Monoclinic gallium oxide, β-Ga<sub>2</sub>O<sub>3</sub>, is a transparent conducting oxide (TCO) that presents one of the widest band gaps among this family materials. Its characteristics make it highly interesting for applications in UV - visible IR optoelectronic and photonic devices. On other hand, morphology nanowires made specific advantages light emitting nanodevices, waveguides gas sensors. Control doping nanostructures utmost importance order to tailor behavior these In work,...
Branched, hierarchically grown ZnGa2O4 and Zn1 − x Mnx Ga2O4 (0.1 < 0.21) micro- nanostructures have been fabricated by a thermal evaporation method. Comparison of both materials shows that the presence Mn favours formation branched morphology, with oriented nanowires high crystalline quality. The origin growth these is discussed. Raman peaks are observed to broaden shift as function content in alloy. Cathodoluminescence analysis structures emit characteristic defect-related UV-blue band...
In this work, a simple thermal evaporation method has been used to obtain variety of Ga<sub>2</sub>O<sub>3</sub>/SnO<sub>2</sub> nano-assemblies with different shapes and dimensionalities, which may affect their physical properties, especially those influenced by surface properties.
In the race toward increasingly high-performance trace-molecule sensors, one of most significant steps forward in last decade for photoacoustic sensors was their combination with high-finesse optical cavities. Validated different configurations, this technique demonstrated enhanced sensitivities below part-per-trillion level (ppt) and record dynamic ranges. Here we present our advanced cantilever-based setup, based on a custom-made silicon cantilever embedded doubly-resonant configuration....
We present our most recent results on trace-gas detection with an intracavity cantilever-enhanced photoacoustic sensor. A full performance analysis is performed using a standard cantilever, and preliminary exploiting alternative configurations are discussed.