A5009808804- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Nanowire Synthesis and Applications
- Copper-based nanomaterials and applications
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and interfaces
- Advanced Semiconductor Detectors and Materials
- Advancements in Semiconductor Devices and Circuit Design
- Ion channel regulation and function
- Gas Sensing Nanomaterials and Sensors
- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- ZnO doping and properties
- Analytical Chemistry and Sensors
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- 2D Materials and Applications
- Transition Metal Oxide Nanomaterials
- Ga2O3 and related materials
- Surface and Thin Film Phenomena
- Thermal Radiation and Cooling Technologies
- Cardiovascular and exercise physiology
- COVID-19 diagnosis using AI
- Strong Light-Matter Interactions
- Digital Imaging in Medicine
Max Planck Institute for Plasma Physics
2025
University of Puerto Rico at Río Piedras
2025
Universidade Federal de Minas Gerais
2015-2024
Instituto de Salud del Estado de México
2019
Universidade Federal de Ouro Preto
2015
Universidade Federal de São Carlos
2009
Universidade Federal do Paraná
2009
Brazilian Synchrotron Light Laboratory
2002-2005
Universidade Estadual de Campinas (UNICAMP)
2004
North Carolina State University
2001-2002
In this work, we investigated structural, morphological, electrical, and optical properties from a set of ${\text{Cu}}_{2}\text{Zn}\text{Sn}{\text{S}}_{4}$ thin films grown by sulfurization metallic precursors deposited on soda lime glass substrates coated with or without molybdenum. X-ray diffraction Raman spectroscopy measurements revealed the formation single-phase films. A good crystallinity grain compactness film was found scanning electron microscopy. The are poor in copper rich zinc,...
The temperature dependence of electrical conductivity and the photoconductivity polycrystalline Cu2ZnSnS4 were investigated. It was found that at high temperatures dominated by band conduction nearest-neighbour hopping. However, lower temperatures, both Mott variable-range hopping (VRH) Efros–Shklovskii VRH observed. analysis transport showed doping levels a large compensation ratio, demonstrating degree disorder in Cu2ZnSnS4. Photoconductivity studies presence persistent effect with decay...
In this report, we propose an AC response equivalent circuit model to describe the admittance measurements of Cu2ZnSnS4 thin film solar cell grown by sulphurization stacked metallic precursors. This describes contact resistances, back contact, and heterojunction with two trap levels. The study resistance allowed estimation a barrier 246 meV. analysis series varying temperature revealed defect activation energies 45 meV 113 cell’s electrical parameters were obtained from J-V curve: conversion...
In the present research it is reported synthesis and characterization of CdS nanoparticles (NPs) prepared using carboxylic-functionalized poly (vinyl alcohol) (PVA) as ligand via aqueous route at room temperature ambient pressure. Different molar concentrations carboxylic-PVA PVA were investigated aiming producing stable colloidal systems. Carboxylic-PVA was conjugated with BSA (bovine serum albumin) used capping in preparation nanocrystals. UV–visible spectroscopy, photoluminescence...
Abstract Thin film solar cells based in Cu(In,Ga)Se 2 (CIGS) are among the most efficient polycrystalline cells, surpassing CdTe and even silicon cells. For further developments, CIGS technology has to start incorporating different cell architectures strategies that allow for very low interface recombination. In this work, ultrathin 350 nm with a rear passivation strategy studied characterized. The is achieved using an Al O 3 nanopatterned point structure. Using results, photoluminescence...
Hyperbolic phonon polaritons have recently attracted considerable attention in nanophotonics mostly due to their intrinsic strong electromagnetic field confinement, ultraslow polariton group velocities, and long lifetimes. Here we introduce tin oxide (SnO2) nanobelts as a photonic platform for the transport of surface volume mid- far-infrared frequency range. This report brings comprehensive description polaritonic properties SnO2 nanometer-sized dielectric also an engineered material form...
We present a study of the structural and quantum conductance properties atomic-size copper nanowires generated by mechanical stretching. The atomistic evolution was derived from time-resolved electron microscopy observations molecular dynamics simulations. have analyzed transport behavior means measurements theoretical calculations. results suggest formation an unusual highly stable pentagonal Cu nanowire with diameter approximately 0.45 nm 4.5 quanta.
The persistent photoconductivity (PPC) effect was studied in individual tin oxide (SnO2) nanobelts as a function of temperature, air, helium, and vacuum atmospheres, low temperature. Photoluminescence measurements were carried out to study the optical transitions determine acceptor/donors levels their best representation inside band gap. Under ultraviolet (UV) illumination at temperatures range 200–400 K, we observed fast strong enhancement photoconductivity, maximum value photocurrent...
In the quest for more sensitive gas sensors, researchers have studied how heating using UV light, and thermally annealing sensors improve performance. During thermal annealing, process can crystallinity of material while also increasing electrode sensing interactions to create available active sites thus sensor Hexadecafluorinated iron (II) phthalocyanine (FePcF16) nanowires high sensitivity towards NH3 selectively, NWs after deposition further response recovery. For this reason, effect...
MoS2 monolayers, a two-dimensional (2D) direct semiconductor material with an energy gap of 1.9 eV, offer many opportunities to be explored in different electronic devices. Defects often play dominant roles the and optical properties However, little experimental information about intrinsic extrinsic defects or impurities is available for this 2D system, even macroscopic 3D samples which shows indirect bandgap 1.3 eV. In work, we evaluate nature unpaired spins using electron paramagnetic...
The structure of the electronic energy levels a single phase Cu2ZnSnS4 film, as confirmed by Raman Scattering and x-ray diffraction, is investigated through dependence on excitation power photoluminescence (PL). behavior observed asymmetric band, with peak at ∼1.22 eV, compared two theoretical models: (i) fluctuating potentials (ii) donor-acceptor pair transitions. It shown that radiative recombination channels in Cu-poor film are strongly influenced tail states bandgap consequence heavy...
Scanning probe microscopy was used to investigate the structural and electrical organization at nanoscopic level of hydrated melanin thin films synthesized by oxidizing L-3-(3,4-dihydroxyphenyl)-alanine (L-dopa) in dimethyl sulfoxide. Atomic force (AFM) provided morphologies L-dopa films. Electrostatic conductive-AFM were spatially resolve properties material. Using a simple parallel plate capacitor model method measure charge distribution on sample developed. The correlations between...
In the present research, concept of developing a novel system based on polymer-enzyme macromolecules was tested by coupling carboxylic acid functionalized poly(vinyl alcohol) (PVA-COOH) to glucose oxidase (GOx) followed bioconjugation with CdS quantum-dots (QD). The resulting organic-inorganic nanohybrids were characterized UV-visible spectroscopy, infrared Photoluminescence spectroscopy (PL) and transmission electron microscopy (TEM). results have clearly shown that (PVA-COOH/GOx)...
We report an investigation on the morphological, structural, and optical properties of large size wurtzite GaAs nanowires, low doped with Mg, grown GaAs(111)B Si(111) substrates. A higher density vertical nanowires was observed when upon GaAs(111)B. Very thin zinc-blende segments are along axis a slightly linear being found Si(111). Low temperature cathodoluminescence photoluminescence measurements reveal emission in range 1.40–1.52 eV related spatial localization charge carriers at...