A5004479591- Semiconductor Quantum Structures and Devices
- Advanced Semiconductor Detectors and Materials
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Semiconductor materials and devices
- GaN-based semiconductor devices and materials
- Diamond and Carbon-based Materials Research
- Nanowire Synthesis and Applications
- solar cell performance optimization
- Integrated Circuits and Semiconductor Failure Analysis
- Advanced Surface Polishing Techniques
- Semiconductor materials and interfaces
- Metal and Thin Film Mechanics
- Advanced Electron Microscopy Techniques and Applications
- Advanced X-ray Imaging Techniques
- Advanced Topics in Algebra
- Technology in Education and Healthcare
- Ga2O3 and related materials
- HIV/AIDS Impact and Responses
- HIV/AIDS Research and Interventions
- HIV-related health complications and treatments
- E-Learning and Knowledge Management
- Organic Electronics and Photovoltaics
- Advanced ceramic materials synthesis
- Advanced Chemical Physics Studies
Stanford University
2025
Universidad de Cádiz
2015-2024
University of Arizona
2023-2024
Universidad Complutense de Madrid
2023-2024
San Juan Bautista School of Medicine
2024
Instituto de Ciencia de Materiales de Sevilla
2022-2023
University of Trieste
2023
University of Wisconsin–Madison
2023
Institut Català d'Investigació Química
2017-2022
Pontificia Universidad Católica de Valparaíso
2015
Diamond, as the densest allotrope of carbon, displays a range exemplary material properties that are attractive from device perspective. Despite diamond displaying high carbon–carbon bond strength, ultrashort (femtosecond) pulse laser radiation can provide sufficient energy for highly localized internal breakdown lattice. The less-dense carbon structures generated on lattice subject to significant pressure surrounding matrix, leading unusual formation conditions. By tailoring dose delivered...
The structure and composition of single GaAsBi/GaAs epilayers grown by molecular beam epitaxy were investigated optical transmission electron microscopy techniques. Firstly, the GaAsBi layers exhibit two distinct regions a varying Bi profile in growth direction. In lower (25 nm) region, content decays exponentially from an initial maximum value, while upper region comprises almost constant until end layer. Secondly, despite relatively low content, CuPtB-type ordering was observed both...
The fabrication of ohmic contacts is a fundamental technological step toward the development and manufacture reliable electronic devices. However, in case diamond-based devices, there lack knowledge related to formation these types contacts. While role interface carbide on refractory–metal/diamond has been reported as key mechanism for thermal stabilization optimization behaviour; still knowledge, at diamond/tungsten (W) interface, structural chemical characteristics versus electrical...
Developing cancer therapies that induce robust death of the malignant cell is critical to prevent relapse. Highly effective strategies, such as immunotherapy, exemplify this observation. Here we provide structural and molecular underpinnings for an approach leverages chemical induced proximity produce specific killing diffuse large B lymphoma, most common non-Hodgkin's lymphoma. We develop KAT-TCIPs (lysine acetyltransferase transcriptional/epigenetic inducers proximity) redirect p300 CBP...
This paper investigates the effect of GaAsBi strain reduction layers (SRLs) on InAs QDs with different Bi fluxes to achieve nanostructures improved temperature stability. The SRLs are grown at a lower (370 °C) than usual capping for (510 °C). study finds that GaAs low temperatures reduces QD decomposition and leads larger pyramidal dots but also increases threading dislocation (TD) density. When adding layer, significant in TD density is observed, unexpected structural changes occur....
The photoluminescence efficiency of GaAsSb-capped InAs/GaAs type II quantum dots (QDs) can be greatly enhanced by rapid thermal annealing while preserving long radiative lifetimes which are ∼20 times larger than in standard GaAs-capped QDs. Despite the reduced electron-hole wavefunction overlap, type-II samples more efficient type-I counterparts terms luminescence, showing a great potential for device applications. Strain-driven In-Ga intermixing during is found to modify QD shape and...
This work analyses the Bi incorporation in InAs1-xBix/InAs(100) epilayers grown by MBE through advanced transmission electron microscopy techniques. Samples from 350–400 °C resulted contents <3.3% exhibiting compositional variation growth direction. In contrast, roughly spherical clusters appeared sample at lower temperatures. The are made up of binary InBi with a tetragonal PbO phase surrounded matrix InAs0.95Bi0.05 indicating solubility limit InAs. These crystals underwent cubic distortion...
The effect of the capping process on morphology InAs/GaAs quantum dots (QDs) by using different GaAs-based layers (CLs), ranging from strain reduction to compensating layers, has been studied transmission microscopic techniques. For this, we have measured simultaneously height and diameter in buried uncapped QDs covering populations hundreds that are statistically reliable. First, QD population evolves all cases a pyramidal shape into more homogenous distribution with spherical-dome shape,...
Multi-junction solar cells made by assembling semiconductor materials with different bandgap energies have hold the record conversion efficiencies for many years and are currently approaching 50%. Theoretical efficiency limits make use of optimum designs right lattice constant-bandgap energy combination, which requires a 1.0-1.15 eV material lattice-matched to GaAs/Ge. Nevertheless, lack suitable is hindering achievement predicted efficiencies, since only candidates were up now complex...
Abstract A theory of partial separability for classical Hamiltonian systems is proposed in the context Haantjes geometry. As a general result, we show that knowledge non-semisimple symplectic-Haantjes manifold given system sufficient to construct sets coordinates (called Darboux-Haantjes coordinates) allow both associated Hamilton-Jacobi equations and block-diagonalization operators corresponding algebra. We also introduce novel class systems, characterized by existence generalized Stäckel...
A procedure to quantitatively analyse the relationship between wetting layer (WL) and quantum dots (QDs) as a whole in statistical way is proposed. As we will show manuscript, it allows determining, not only proportion of deposited InAs held WL, but also average In content inside QDs. First, amount measured for calibration three different WL structures without QDs by two methodologies: strain mappings high-resolution transmission electron microscopy images compositional with ChemiSTEM x-ray...
The possibility of an independent tuning the electron and hole confinement in InAs/GaAs quantum dots (QDs) by using a thin GaAsSbN capping layer (CL) is studied. By controlling Sb N contents quaternary alloy, band structure QDs can be broadly tuned converted from type-II valence (high contents) to type-I conduction contents). Nevertheless, simultaneous presence found induce strain composition inhomogeneities CL degrade photoluminescence structure.
As promising candidates for solar cell and photodetection applications in the range 1.0–1.16 eV, growth of dilute nitride GaAsSbN alloys lattice matched to GaAs is studied. With this aim, we have taken advantage temperature gradient molecular beam epitaxy reactor analyse impact on incorporation Sb N species according wafer radial composition gradients. The results from combination X-ray diffraction (XRD) energy-dispersive spectroscopies (EDS) show an opposite rate between as move away centre...
Recently, thin AlAs capping layers (CLs) on InAs quantum dot solar cells (QDSCs) have been shown to yield better photovoltaic efficiency compared traditional QDSCs. Although it has proposed that this improvement is due the suppression of capture photogenerated carriers through wetting layer (WL) states by a de-wetting process, mechanisms operate during process are not clear. In work, structural analysis WL characteristics in AlAs/InAs QD system with different CL-thickness made scanning...
The use of GaAsSbN capping layers on InAs/GaAs quantum dots (QDs) has recently been proposed for micro- and optoelectronic applications their ability to independently tailor electron hole confinement potentials. However, there is a lack knowledge about the structural compositional changes associated with process simultaneous Sb N incorporation. In present work, we have characterized using transmission microscopy techniques effects adding in GaAsSb/InAs/GaAs QD system. Firstly, strain maps...
Paper presents simulation and operation of a mobile robot using GPS in navigation. It is used SLAM algorithm to obtain map, path planner called Wavefront, VHF navigation obstacle evasion algorithm. A Player/Stage utilized the real tested.
The optical and structural properties of GaAsBi bulk quantum well (QW) samples grown under various conditions were studied by photoluminescence (PL), high resolution x-ray diffraction (HR-XRD) transmission electron microscopy (TEM). At 10 K, the 90 nm sample shows two PL peaks at 1.18 1.3 eV. temperature power dependent data suggest that both originate from layer which consists regions with different Bi concentrations. TEM images verify concentration decreases monotonically across layer,...
The application of a GaAsSb/GaAsN short-period superlattice capping layer (CL) on InAs/GaAs quantum dots (QDs) is shown to be an option for providing improved luminescence properties this system. Separating both GaAsSb and GaAsN ternaries during the growth in 2 monolayer-thick phases solves GaAsSbN immiscibility-related problems. Strong fluctuations CL composition strain field as well QD size distribution are significantly reduced, more regular interface also obtained. Room-temperature (RT)...
Changing the growth rate during heteroepitaxial capping of InAs/GaAs quantum dots (QDs) with a 5 nm-thick GaAsSbN layer (CL) strongly modifies QD structural and optical properties. A size shape transition from taller pyramids to flatter lens-shaped QDs is observed when CL decreased 1.5 0.5 ML/s. This indicates that dissolution processes taking place can be controlled some extent by rate, high rates allowing complete preservation QDs. However, are shown have leveling effect on height, giving...