FERMIN FIDEL HERRERA ARAGON
@international.unb.br
University of Brasilia - UnB
Collaborator Researcher
Fermin F. H. Aragon received his PhD degree from the University of Brasılia (2013), Brazil. He was a postdoctoral fellow at the Center for the Development of Nuclear Technology (CDTN) and Visiting Professor at the Physics Institute of the University of Brasilia, Brazil (2016–2019), Research fellow at the Center for Biomedical Research (CBR) of the Population Council located at Rockefeller University, New York (2020).Associate Researcher at the Pontifical Catholic University of Peru (PUCP), Associate Researcher at the National University of San Agustin of Arequipa (UNSA), Peru(2022). His research work mainly focuses on the production and studying of the structural, optical, electrical, hyperfine, and magnetic properties of nanomaterials, with technological applications such as gas sensors, photocatalysis, wastewater treatment process, and biomaterials for health applications.
RESEARCH INTERESTS
Nanomaterials syntheses and characterization, thin film, nanoparticles.
Scopus Publications
Scopus Publications
F.F.H. Aragón, L. Villegas-Lelovsky, J.G. Parizaka, E.G. Zela, R. Bendezu, R.O. Gallegos, J.A.H. Coaquira, D.G. Pacheco-Salazar, S.W. da Silva, J. Garnier,et al.
Elsevier BV
J. R. Velasquez-Ordoñez, J. Rivera-Taco, D. G. Pacheco-Salazar, J. A. H. Coaquira, J. L. Maldonado, J. A. Guerra, P. Llontop, P. C. Morais, and F. F. H. Aragón
AIP Publishing
A successful hexagonal Cu2S p-type semiconductor thin film using DC magnetron sputtering is reported. Films with thickness gradients were deposited by taking advantage of deposition geometry and target dimensions. X-ray diffraction (XRD) analysis confirmed the exclusive formation of the hexagonal Cu2S phase. Elemental composition and thickness dependence with the sample position were determined using energy-dispersive x-ray spectroscopy. Optical properties, including the optical bandgap, refractive index, and extinction coefficient, were assessed by modeling transmittance spectra. The Tauc–Lorentz oscillator and Drude models were employed for this purpose. XRD data analysis successfully determined the film thickness (tXRD) as a function of the sample position, aligning well with thickness values (tT) derived from transmittance spectra analyses. These results were further supported by film thickness values (tSEM) obtained from cross-sectional SEM images. Charge carrier density and mobility, extracted from the optical models, were found to be consistent with DC electrical measurements. AC impedance curves were effectively modeled with RL–RC parallel circuits. The results indicate that the inductance (L) and capacitance (C) components of the films increase with decreasing film thickness.
Leonardo Vieira Albino, Nicole Gouveia Roque, Lia Mara Marcondes, Juliane Resges Orives, Douglas Faza Franco, Renata Siqueira Manzan, Fermin Herrera Aragón, Jorlandio Francisco Felix, and Marcelo Nalin
Elsevier BV
T.J. Castro, E.J.F. Conceição, F.F.H. Aragón, J.A.H. Coaquira, P.C. Morais, and S.W. da Silva
Elsevier BV
E.J.F. Conceição, F.F.H. Aragón, Y.A. Urian, T.J. Castro, J.A.H. Coaquira, P.C. Morais, and S.W. da Silva
Elsevier BV
F. F. H. Aragón, L. Villegas-Lelovsky, J. I. Castillo-Llanos, C. M. Soncco, J. L. Solis, G. H. Peralta-Alarcón, D. G. Pacheco-Salazar, and P. C. Morais
Royal Society of Chemistry (RSC)
Tuning the physical properties of Cu-doped SnO2 NPs to potential use as self-cleaning surfaces.
S.A. De la Torre Pari, J.C.R. Aquino, A.F. Carlos-Chilo, J.A. Guerra, J.A.H. Coaquira, D.G. Pacheco-Salazar, J.F. Felix, J.L. Solis, and F.F.H. Aragón
Elsevier BV
F. M. de Oliveira, L. Cabral, L. Villegas-Lelovsky, Matheus P. Lima, F. F. H. Aragón, G. E. Marques, A. J. Chiquito, and M. D. Teodoro
Royal Society of Chemistry (RSC)
In this work, carrier transport in a gold-seeded zinc diphosphide nanowire fabricated by vapor–liquid–solid and photolithography techniques is investigated in detail.
F. F. H. Aragón, L. Villegas-Lelovsky, J. G. Parizaka, E. G. Zela, R. Bendezu, R. O. Gallegos, D. G. Pacheco-Salazar, S. W. da Silva, R. Cohen, L. C. C. M. Nagamine,et al.
Royal Society of Chemistry (RSC)
When Fe-ions enter into the ZnO NPs, their oxidation state can be tuned and the excitonic peak enlarges, indicating that the ZnO lattice becomes more disordered. The AFM interactions found in paramagnetic NPs become stronger as Fe content increases.
M. Huanca Ccamerccoa, N. L. Tapia Falcon, L. León Félix, D. G. Pacheco-Salazar, F. F. H. Aragón, J. A. H. Coaquira, Jéremie Garnier, and C. Vera-Gonzales
Springer Science and Business Media LLC
K J Paz-Corrales, C A Vilca-Huayhua, F F H Aragón, L Villegas-Lelovsky, J A H Coaquira, S W da Silva, G E Marques, M D Teodoro, and D G Pacheco-Salazar
IOP Publishing
Abstract The control of native defects in the ZnO material is strongly important for a wide range of technological applications. In this paper, native defects are tuned via the post-thermal treatment of ZnO films in a high vacuum atmosphere. The microstructure of the as-grown ZnO film shows columnar growth and strongly polar-oriented grains along the c-plane (002). Also, the obtained results indicate that the as-grown film contains a high amount of intrinsic defects and strong lattice distortions. After the thermal annealing, the ZnO films display significant structural changes, which are reflected in their electrical, vibrational, and optical properties. Our findings suggest that these changes were attributed to the selective cleanup effect of the native defects and the partial deoxidation process mainly on the exposed particle surface (at high temperatures) tuned up by the thermal annealing temperature. According to DFT calculations, oxygen vacancies (V O ) show lower energy, followed by zinc vacancies (V Zn ) and oxygen interstitials (O i ) indicating that V O defect is the most stable in ZnO. That sequence of stability could suggest the sequence of the annihilation of those defects, which is in line with our experimental findings and also in agreement with literature results.
P Llontop, C E Torres, M Piñeiro, L Conde, A Tejada, J A Töfflinger, F Rumiche, F F H Aragón, D G Pacheco-Salazar, R Grieseler,et al.
IOP Publishing
Abstract The effect of adding terbium to indium tin oxide (ITO) thin films on the electrical, optical and light emission properties was investigated. The films were prepared by radio frequency dual magnetron sputtering, maintaining a high optical transmittance in the ultraviolet and visible spectral regions, and a low electrical resistivity ranging from 5 × 10 − 3 Ω ⋅ cm to 0.3 Ω ⋅ cm . Terbium-related luminescence is achieved after annealing at 470 ∘C in air at atmospheric pressure. Electrical resistivity and optical transmittance were measured after each annealing step to evaluate the compromise between the achieved light emission intensity, electrical and optical properties. Additionally, temperature dependence of Tb-related luminescence quenching was assessed by temperature-dependent photoluminescence measurements, from 83 to 533 K, under non-resonant excitation. Thermal quenching activation energies suggest an effective energy transfer mechanism from the ITO host to the rare-earth (RE) ions. This indirect excitation mechanism was modeled using a spherical potential-well and a tight-binding one-band approximation approaches, describing a short-range charge trapping process and subsequent formation of bound excitons to RE ion clusters.
Carlos D. Gonzales-Lorenzo, Darwin J. Callo-Escobar, Alberto A. Ccollque-Quispe, T.K. Gundu Rao, F.F.H. Aragón, J.C.R. Aquino, D.G. Pacheco-Salazar, H. Loro, Jose F. Benavente, Jessica Mosqueira-Yauri,et al.
Optical Materials Elsevier BV
S. C. Andia-Huaracha, L. M. Zapana-Cayo, F. F. H. Aragón, J. C. Romero Aquino, J. A. H. Coaquira, C. D. Gonzales-Lorenzo, J. S. Ayala-Arenas, J. L. Solis, P. C. Morais, and D. G. Pacheco-Salazar
Springer Science and Business Media LLC
T.J. Castro, F.F.H. Aragón, E.J.F. Conceição, J.A.H. Coaquira, P.C. Morais, and S.W. da Silva
Elsevier BV
G.B. Oliveira-Filho, J.J. Atoche-Medrano, F.F.H. Aragón, J.C. Mantilla Ochoa, D.G. Pacheco-Salazar, S.W. da Silva, and J.A.H. Coaquira
Elsevier BV
Lalit Kumar Gaur, Preeti Gairola, S.P. Gairola, Mohan Chandra Mathpal, Promod Kumar, Sachin Kumar, Dushyant Kushavah, Vivek Agrahari, F.F.H. Aragon, Maria A.G. Soler,et al.
Elsevier BV
F.F.H. Aragón, J.A.H. Coaquira, S.W. da Silva, R. Cohen, D.G. Pacheco-Salazar, and L.C.C.M. Nagamine
Journal of Alloys and Compounds Elsevier BV
Lizbet León Félix, Joaquin Martinez Porcel, Fermín Fidel Herrera Aragón, David Gregorio Pacheco-Salazar, and Marcelo Henrique Sousa
Springer Science and Business Media LLC
AbstractWe describe a simple method for the preparation of gold-decorated silica (SiO2) nanoparticles (NPs) by the in situ precipitation method using simple BH4− ions reduction as a procedure, where BH4− ions are adsorbed onto PEI-functionalized SiO2 NPs for stabilizing and reducing gold ions onto PEI-SiO2 surface in water under ambient conditions. The result was 3-nm gold nanoshell NPs attached to SiO2 core (~ 75 nm) with a surface plasmon resonance (SPR) at ~ 680 nm. SPR band is associated with Au NP aggregates that arise from strong interparticle interaction. This is an alternative to the gold-seeding methods and the use of anionic gold species for the obtention of gold-decorated SiO2 NPs with an important red-shift in UV–Vis absorption and with potential applications in biosensors and photothermal therapy.
F. F. H. Aragón, L. Villegas-Lelovsky, L. Cabral, M. P. Lima, A. Mesquita, and J. A. H. Coaquira
Royal Society of Chemistry (RSC)
We present an accurate study of the mechanisms involved in the oxidation states of Ce-ions during the doping process of SnO2 nanoparticles prepared by the polymeric precursor method.
Gopal Niraula, Jose A.H. Coaquira, Fermin H. Aragon, Bianca M. Galeano Villar, Alexandre Mello, Flavio Garcia, Diego Muraca, Giorgio Zoppellaro, Jose M. Vargas, and Surender K. Sharma
Elsevier BV
Fermin F.H. Aragon, Clement M. Haeck, Paulo C. Morais, and Bruce Variano
Elsevier BV
Gopal Niraula, Jose A. H. Coaquira, Fermin H. Aragon, Andris F. Bakuzis, Bianca M. G. Villar, Flavio Garcia, Diego Muraca, Giorgio Zoppellaro, Ahmad I. Ayesh, and Surender K. Sharma
American Physical Society (APS)
The generation of topological magnetic vortex-domain structures in iron-oxide nanomaterials has promising applications in biomedical scenarios, such as heat generators for hyperthermia treatments. In this report we describe alternative kinds of magnetic-vortex nanoparticles, circular ${\\mathrm{Fe}}_{3}{\\mathrm{O}}_{4}$ nanodiscs (NDs), and dissect their heating properties by in-depth investigation of their shape and size, stoichiometry, orientations, and switching field ``${H}_{S}$'' behaviors, through experiments and theoretical simulation. We find that the stoichiometric NDs show better heating performance than nonstoichiometric materials because of the significant electron hopping between ${\\mathrm{Fe}}^{3+}$ and ${\\mathrm{Fe}}^{2+}$ ion. The higher heating efficiency (in terms of specific absorption rate, SAR) is observed only for the higher switching field regime, an effect that is associated with the parallel and perpendicular alignment of nanodiscs with respect to low and high ac magnetic field, respectively. A higher SAR of approximately 270 W/g is observed at a higher switching field (approximately 700 Oe) for NDs of diameter 770 nm, which increases by a factor of 4 at a switching field of approximately 360 Oe for NDs of diameter 200 nm. The reported results suggest that the heating efficiency in these systems can be enhanced by controlling the switching field, which is, in turn, tuned by size, shape, and orientation of circular magnetic vortex nanodiscs.
John Mantilla, Marco Morales, Wenderson Venceslau, Laura Corredor, P.C. Morais, Fermin F.H. Aragón, Sebastião William da Silva, and Jose A. Coaquira
Elsevier BV
D.G. Pacheco-Salazar, F.F.H. Aragón, L. Villegas-Lelovsky, A. Ortiz de Zevallos, G.E. Marques, and J.A.H. Coaquira
Elsevier BV