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Autor Piqueras de Noriega, Javier |
Documentos disponibles escritos por este autor (322)
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Maestre Varea, David ; Cremades Rodríguez, Ana Isabel ; Piqueras de Noriega, Javier | IOP publishing ltd | 2004-11Remote electron beam induced current (REBIC) and cathodoluminescence (CL) modes in the scanning electron microscope (SEM) have been used to investigate SnO2 sintered samples. The study of the electrically active boundaries present in the oxide s[...]texto impreso
Nogales Díaz, Emilio ; López, I. ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Lorenz, K. ; Alves, E. ; García, J.A. | Spie-Int Soc Optical Engineering | 2012Monoclinic gallium oxide, beta-Ga_2O_3, is a transparent conducting oxide (TCO) that presents one of the widest band gaps among this family of materials. Its characteristics make it highly interesting for applications in UV - visible - IR optoel[...]texto impreso
Nogales Díaz, Emilio ; García, José Angel ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier | Amer Inst Physics | 2007-09-24Er and Cr doped ß-Ga_2O_3 nano- and microwires have been grown by thermal treatments of Ga2O3 powder containing a fraction of Er_2O_3 powder or in the presence of Cr_2O_3 powder, respectively. Doping gives rise to the characteristic red photolum[...]texto impreso
López, I. ; Nogales Díaz, Emilio ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier | Spie-Int Soc Optical Engineering | 2014Ga_2O_3 bulk single crystals have been implanted with 300 keV Europium ions to fluences ranging from 1x10^(13) to 4x10^(15) at/cm^(2). The damage build-up and Eu-incorporation was assessed by Rutherford Backscattering Spectrometry in the channel[...]texto impreso
Plaza, J. L. ; Hidalgo Alcalde, Pedro ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Castaño, J. L. ; Dieguez, E. | Elsever science BV | 1999-03The distribution of Er in bulk GaSb ingots grown by vertical Bridgman technique has been investigated for different concentrations. The resistivity, mobility and carrier density were analysed. The formation of Er-Sb compounds and the incorporati[...]texto impreso
Hidalgo Alcalde, Pedro ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Plaza, J. ; Dieguez, E. | IOP publishing ltd | 1998-12GaSb single crystals with different Er concentrations have been studied by cathodoluminescence in the scanning electron microscope. Low Er doping has been found to reduce the concentration of native accepters. In crystals with higher Er concentr[...]texto impreso
Hidalgo Alcalde, Pedro ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Plaza, J. L. ; Dieguez, E. | Trans Tech-Scitec Publications LTD | 1998The interest of rare earth doping of semiconductors has increased in the last years due to its possible applications in optical devices requiring temperature stability. Advantages of these systems are the presence of a sharp temperature independ[...]texto impreso
Panin, G. N. ; Piqueras de Noriega, Javier ; Sochinskii, N. ; Dieguez, E. | Amer Inst Physics | 1997-02-17The a?-HgI_2/CdTe:Ce heterostructures have been studied by cathodoluminescence (CL) in the scanning electron microscope. The alpha-HgI2 expitaxial growth was shown to cause an enhancement of the CL intensity in a layer of the substrate extending[...]texto impreso
Hidalgo Alcalde, Pedro ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Dutta, P: S. ; Dieguez, E. | IOP publishing ltd | 1999-10The luminescence properties of In doped GaSb single crystals have been studied by the cathodoluminescence (CL) technique in the scanning electron microscope. It has been found that indium induces a certain reduction on the native acceptor concen[...]texto impreso
Panin, G. N. ; Fernández Sánchez, Paloma ; Piqueras de Noriega, Javier | IOP publishing ltd | 1996-09The effect of ion milling on the defect structure of CdTe crystals has been investigated in the scanning electron microscope by cathodoluminescence. Enhancement in the luminescence intensity is observed after ion treatment. Luminescence spectra [...]texto impreso
Zaldivar, M.H. ; Fernández Sánchez, Paloma ; Piqueras de Noriega, Javier ; Solís, J. | American Institute of Physics | 1999-01-15Pulsed laser treatments have been performed in GaN samples of both n- and p-type conductivity. The laser induced changes have been monitored by emissive mode and cathodoluminescence (CL) in a scanning electron microscope. Emissive mode observati[...]texto impreso
Fernández Sánchez, Paloma ; Piqueras de Noriega, Javier ; Urbieta Quiroga, Ana Irene ; Rebane, Y. T. ; Shreter, Y. G. | Trans Tech-Scitec Publications LDT | 1998The electronic recombination properties of defects in ZnSe is a subject of interest related to the application of this material in optoelectronic devices operating in the blue-green range. In this work the influence of defects, in particular the[...]texto impreso
Maestre Varea, David ; Plugaru, R ; Cremades Rodríguez, Ana Isabel ; Piqueras de Noriega, Javier | Materials Research Society | 2003The luminescence of titanium oxide and tin oxide has been investigated by cathodoluminescence in the SEM, as a function of the structural changes induced by thermal treatments. The evolution of the luminescence of TiO2 rutile, anatase and mixtur[...]texto impreso
Cristian Vasquez, G. ; Andrea Peche-Herrero, M. ; Maestre Varea, David ; Cremades Rodríguez, Ana Isabel ; Ramirez-Castellanos, Julio ; María Gonzalez-Calbe, José ; Piqueras de Noriega, Javier | Amer Chemical Soc | 2013-01-31Rutile TiO_2 nanoparticles doped with V, Cr, or Mn ions have been synthesized via a modified Pechini method using polymeric precursors. The final particle sizes range between 20 and 500 nm depending on the selected dopant. The TiO_2 rutile phase[...]texto impreso
Plaza, J. L. ; Hidalgo Alcalde, Pedro ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Castaño, J. L. | Elsevier Science SA | 2001-04-24In this work pure and Gd-doped GaSb ingots with different dopant concentrations were grown by the Bridgman Method. The compositional and electrical analysis carried out on these materials have shown the dependence of these results on the initial[...]texto impreso
Castaldini, A. ; Cavallini, A. ; Polenta, L. ; Díaz-Guerra Viejo, Carlos ; Piqueras de Noriega, Javier | IOP publishing ltd | 2002-12-16The study of the effect of extended defects, present in very large numbers in GaN epilayers, on the material properties and device performance is one of the most important aims of the current research in the field of III nitrides. Thickness stro[...]texto impreso
Nogales Díaz, Emilio ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Plugaru, R | IOP publishing ltd | 2003-01Nanocrystalline silicon films, with an average nanocrystal size of about 10 nm, obtained by boron implantation of amorphous silicon layers, have been studied by remote-beam-induced current (REBIC) in a scanning tunnelling microscope (STM) and by[...]texto impreso
Díaz-Guerra Viejo, Carlos ; Piqueras de Noriega, Javier | American Institute of Physics | 1999-08-15A correlative study of the electrically active grain boundary structure of ZnO polycrystals has been carried out using a scanning electron microscope/scanning tunneling microscope (SEM/STM) combined instrument. Current imaging tunneling spectros[...]texto impreso
Herrera, M. ; Cremades Rodríguez, Ana Isabel ; Stutzmann, M. ; Piqueras de Noriega, Javier | Academic Press Ltd- Elsevier Science Ltd | 2009-04Mn doped GaN films have been studied by conductive Atomic Force Microscopy (AFM), Cathodoluminescence (CL) and Electron Beam Induced Current (EBIC). AFM measurements revealed the presence of pinholes with diameters between 130 and 380 nm. The di[...]texto impreso
Herrera, M. ; Cremades Rodríguez, Ana Isabel ; Stutzmann, M. ; Piqueras de Noriega, Javier | Academic Press Ltd- Elsevier Science Ltd | 2009-04Mn doped GaN films have been studied by conductive Atomic Force Microscopy (AFM), Cathodoluminescence (CL) and Electron Beam Induced Current (EBIC). AFM measurements revealed the presence of pinholes with diameters between 130 and 380 nm. The di[...]texto impreso
Díaz-Guerra Viejo, Carlos ; Piqueras de Noriega, Javier ; Tomashpolsky, Y. Y. ; Sadovskaya, N. V. ; Opagiste, C. | IOP publishing ltd | 1996-09Tl_2Ba-2CuO_(6+?) ceramics have been irradiated in a scanning electron microscope. The resultant changes in the cationic stoichiometry and oxygen content of the samples were investigated by cathodoluminescence (CL), secondary electron emission ([...]texto impreso
Cremades Rodríguez, Ana Isabel ; Piqueras de Noriega, Javier | American Institute of Physics | 1999-02-01In the present work, electron beam induced current (EBIC) has been applied to characterize several kinds of chemical vapor deposition diamond films. Regions of enhanced carrier recombination are detected in plan-view observations of thin films a[...]texto impreso
Panin, G. N. ; Díaz-Guerra Viejo, Carlos ; Piqueras de Noriega, Javier | IOP publishing ltd | 1998-06A combined scanning electron microscope-scanning tunnelling microscope (SEM-STM) system has been used to characterize CdxHg1-xTe and CdTe crystals, The electron beam induced current (EBIC) mode of the SEM shows the existence of inhomogeneities i[...]texto impreso
Cremades Rodríguez, Ana Isabel ; Piqueras de Noriega, Javier ; Schreck, M. | Elsevier Science SA | 1997-01Electron beam-induced current (EBIC) is applied to the characterization of chemical vapor-deposited (CVD) diamond films. EBIC contrast shows a strong dependence on the orientation of grains relative to the incident electron beam. This is due to [...]texto impreso
Electrically active defects in epitaxial, n-type, 4H-SiC have been investigated by electron-beam-induced current (EBIC) in the scanning electron microscope. Several defects, mainly nanopipes, 6H polytype inclusions and triangular, carrot-like, d[...]texto impreso
Díaz-Guerra Viejo, Carlos ; Piqueras de Noriega, Javier ; Tomashpolsky, Y. Y. ; Sadovskaya, N. V. | Springer | 1997-04Bi_2Sr_2CaCu_2O_(8+x) superconducting ceramics have been irradiated in the scanning electron microscope (SEM), and the irradiation-induced effects investigated by cathodoluminescence (CL), secondary electron emission (SEE) and X-ray microanalysi[...]texto impreso
Sochinskii, N. V. ; Dieguez, E. ; Pal, U. ; Piqueras de Noriega, Javier ; Fernández Sánchez, Paloma ; Agullorueda, F. | IOP publishing ltd | 1995-06Undoped and doped CdTe wafers have been thermally annealed in Ga melt, or in Cd vapour or in a vacuum to eliminate Te precipitates from the volume of the wafers. The effect of annealing conditions on the transformation of Te precipitates has bee[...]texto impreso
Bazta, Otman ; Urbieta Quiroga, Ana Irene ; Piqueras de Noriega, Javier ; Fernández Sánchez, Paloma ; Addou, M. ; Calvino, J.J. ; Hungría, A.B. | Elsevier Science SA | 2019-11-05Pure ZnO and ZnO: 2%Y:x%Li (x = 0, 3, 5 and 7 at.%) thin films have been successfully prepared onto glass substrates under optimized conditions by spray pyrolysis technique at 450 ºC and their suitability for the fabrication of efficient optoele[...]texto impreso
Plaza, J. L. ; Hidalgo Alcalde, Pedro ; Piqueras de Noriega, Javier ; Dieguez, E. | Sociedad Española de Cerámica y Vidrio | 2000-07En este trabajo se ha realizado el estudio de cristales de GaSb crecidos por el método Bridgman y dopados con Er y Nd con distintas concentraciones. Se han realizado análisis de absorción atómica pudiéndose obtener el coeficiente de segregación [...]texto impreso
Nogales Díaz, Emilio ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Garcia, J. A. | IOP publishing ltd | 2009-03-18Cathodoluminescence and photoluminescence techniques have been used to investigate room temperature light emission from ß-Ga_2O_3:Eu nanostructures, which were obtained by two methods. In one of them, a mixture of Ga_2O_3/Eu2O3 powders was used [...]texto impreso
Piqueras de Noriega, Javier ; Díaz-Guerra Viejo, Carlos ; Vila Santos, María | American Institute of Physics | 2010-05-10Exchange anisotropy has been observed and investigated in single-crystalline CuO nanowires grown by thermal oxidation of Cu. The exchange bias field decreases by increasing temperature and can be tuned by the strength of the cooling field. A tra[...]texto impreso
Miroiu, F. ; Fernández Sánchez, Paloma ; Piqueras de Noriega, Javier | Wiley-V C H Verlag Gmbh | 2006Fabrication of low dimensional structures of II-VI compounds as nanoparticles and elongated structures, such as nanowires or nanotubes, is a subject of increased interest due to their potential use in different technological applications. The ai[...]texto impreso
Piqueras de Noriega, Javier ; Alemán Llorente, Belén ; Ortega Villafuerte, Yanicet ; García Martínez, José Ángel | American Institute of Physics | 2011-07-01Fe dopedZnO nanowires,nanorods, and urchin-like nanostructures have been grown using an evaporation-deposition method with compacted mixtures of ZnS and Fe_2O_3 powders, with different Fe contents as precursors. Treatments at 950 °C under argon [...]texto impreso
López, Iñaki ; Nogales Díaz, Emilio ; Hidalgo Alcalde, Pedro ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier | Wiley-V C H Verlag Gmbh | 2012-01The field emission properties of gallium oxide nanowires grown by thermal evaporation-deposition have been investigated inside the chamber of a scanning electron microscope. Turn on electric fields and enhancement factors have been determined fo[...]texto impreso
Maestre Varea, David ; Cremades Rodríguez, Ana Isabel ; Piqueras de Noriega, Javier | IOP publishing ltd | 2006-03-28Samples of rutile TiO2 have been prepared by sintering compacted powders under argon flow. Long (above 20 h) sintering times at 1500 degrees C led to the formation of rods with squared cross-sections in a broad range of sizes. A two-step anneali[...]texto impreso
Díaz-Guerra Viejo, Carlos ; Almodóvar, P. ; Camacho López, M. ; Camacho López, S. ; Piqueras de Noriega, Javier | Elsevier Science SA | 2017-10-05The formation of different phases of Bi?O? induced by laser irradiation of Bi films has been assessed in situ by micro-Raman spectroscopy as a function of laser wavelength, power density and irradiation time. Raman mapping of the irradiated samp[...]texto impreso
Storgards, J. ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier ; Chenot, M. ; Dimroth, F. ; Bett, A.V. | IOP publishing ltd | 2004-07The effect of electrochemical etching of n-type GaSb in aqueous solutions of HCl and HF has been analysed. By anodization in HCl, two different morphologies of porous layers were observed depending on the current density. At low current density [...]texto impreso
López, I. ; Castaldini, A. ; Cavallini, A. ; Nogales Díaz, Emilio ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier | IOP publishing ltd | 2014-10-15The behaviour of ß-Ga?O? nanowires as photoconductive material in deep ultraviolet photodetectors to operate in the energy range 3.0-6.2 eV has been investigated. The nanowires were grown by a catalyst-free thermal evaporation method on gallium [...]texto impreso
Hidalgo Alcalde, Pedro ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier | IOP publishing ltd | 2005-11Thermal treatment of compacted GeO_2 powder under argon flow leads to the growth of a dense distribution of microwires and nanowires on the sample surface. Extended treatment causes the formation of more complex structures, including arrays of n[...]texto impreso
Hidalgo Alcalde, Pedro ; Liberti, Emanuela ; Rodriguez lazcano, Yamilet ; Méndez Martín, Bianchi ; Piqueras de Noriega, Javier | Amer Chemical Soc | 2009-10-01GeO_2 nanowires doped with Eu, Er, or Mn, as well as codoped with each of these ions and Sri, have been grown by a catalyst-free vapor-solid process. The incorporation of Sri has been found, in all cases, to favor the formation of straight wires[...]texto impreso
Ortega Villafuerte, Yanicet ; Fernández Sánchez, Paloma ; Piqueras de Noriega, Javier | Amer Scientific Publishers | 2010-01Rare-earth (RE) ions are widely investigated luminescent centers because their intraionic-4f transitions generate narrow and intense emission lines. In this work Eu doped ZnO nanoneedles have been grown, by a thermal evaporation-deposition metho[...]texto impreso
Sochinskii, N. V. ; Saucedo, E. ; Abellan, M. ; Rodríguez Fernández, José ; Hidalgo Alcalde, Pedro ; Piqueras de Noriega, Javier ; Ruiz, C.M. ; Bermudez, V. ; Dieguez, E. | Elsevier Science BV | 2008-04Cadmium telluride (CdTe) crystals and epitaxial layers were grown by the vertical Bridgman method and vapor-phase epitaxy, respectively, to obtain the high-resistive material suitable for X- and gamma-ray detectors. The crystals and layers were [...]texto impreso
Piqueras de Noriega, Javier ; Ryu, Y. K. ; Fernández Sánchez, Paloma | Wiley-V C H Verlag Gmbh | 2011-04Er-doped ZnO nano- and microstructures have been grown by thermal treating of compacted mixtures of ZnO and Er_2O_3 powders and their optical properties have been studied by cathodoluminescence (CL). Annealing the pressed samples leads to the gr[...]texto impreso
Herrera, Manuel ; Maestre Varea, David ; Cremades Rodríguez, Ana Isabel ; Piqueras de Noriega, Javier | Amer Chemical Soc | 2013-05-02Undoped and Mn doped SnO_2 nanowires, nanobelts, and microplates have been grown by a thermal evaporation method that enables the morphology and the Mn content in the structures to be controlled. The structural and morphological characterization[...]texto impreso
Maestre Varea, David ; Cremades Rodríguez, Ana Isabel ; Piqueras de Noriega, Javier | American Institute of Physics | 2005Micro- and nanotubes, and other elongated structures of SnO_2 as wires and rods, were grown after sintering in argon flow at temperatures ranging from 1350 degrees C to 1500 degrees C. The morphology and luminescence properties of these structur[...]texto impreso
Magdas, D.A. ; Cremades Rodríguez, Ana Isabel ; Piqueras de Noriega, Javier | Amer Inst Physics | 2006-03-13Indium oxide elongated micro- and nanostructures have been grown by thermal treatment of InN powder. Chains of nanopyramids connected by nanowires, forming a necklace-like structure, as well as cubes and arrow-like structures consisting of a lon[...]texto impreso
Maestre Varea, David ; Cremades Rodríguez, Ana Isabel ; Gregoratti, Luca ; Piqueras de Noriega, Javier | Amer Scientific Publishers | 2008-12Titanium oxide nanowires have been grown by thermal treatment of pressed TiN powder under argon or N-2 flow. It has been found that two-step treatments at two different temperatures, 400 degrees C and 800 degrees C, lead to the growth of nanowir[...]texto impreso
Urbieta Quiroga, Ana Irene ; Fernández Sánchez, Paloma ; Piqueras de Noriega, Javier | Trans Tech Publications Ltd | 2008Sintering of a ZnO-MgO powder mixture under argon flow leads to the growth of elongated Mg doped ZnO structures such as stacks of nanoplates and rods with secondary nanowires in a comb-like arrangement. The nanoplates grow perpendicular to a cen[...]texto impreso
Ortega Villafuerte, Yanicet ; Fernández Sánchez, Paloma ; Piqueras de Noriega, Javier | IOP publishing ltd | 2007-03-21Sintering of a ZnO-SnO_2 mixture under argon flow leads to the growth of microrods on the sample surface, which are formed by oriented stacks of nanoplates. Energy dispersive spectroscopy and cathodoluminescence ( CL) in the scanning electron mi[...]