Person:
Hidalgo Alcalde, Pedro

First Name

Pedro

Last Name

Hidalgo Alcalde

URI

https://hdl.handle.net/20.500.14352/75106

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Físicas

Department

Física de Materiales

Area

Ciencia de los Materiales e Ingeniería Metalúrgica

Identifiers

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Now showing 1 - 9 of 9

Scanning tunneling spectroscopy study of erbium doped GaSb crystals
(Journal of Applied Physics, 1999) Hidalgo Alcalde, Pedro; Méndez Martín, Bianchi; Piqueras de Noriega, Javier; Plaza, J. L.; Dieguez, E.
Er doped GaSb single crystals have been studied by scanning tunneling spectroscopy (STS) and cathodoluminescence (CL) in a combined scanning electron microscope-scanning tunnelling microscope system. The surface band gap in doped samples has been found to be about 0.5 eV while in undoped crystals the gap is close to the bulk value. Inhomogeneities in the local electronic properties of the doped crystals are studied by a correlation of the CL images and STS data.
Electrical and compositional properties on Bridgman-grown Gd-doped GaSb substrates
(Materials Science and Engineering B-Solid State Materials for Advanced Technology, 2001) Plaza, J. L.; Hidalgo Alcalde, Pedro; Méndez Martín, Bianchi; Piqueras de Noriega, Javier; Castaño, J. L.
In 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 dopant concentration. The analysis have revealed the presence of inclusions which have been identified as Gd-Sb precipitates. The doped material was found to be p-type with a maximum value of the carrier density at the central region of the ingots. It has been also demonstrated that the Gd enhances the A band emission reducing the band-gap emission.
Study of the defect structure, compositional and electrical properties of Er_2O_3-doped n-type GaSb : Te crystals grown by the vertical Bridgman technique
(Materials Science and Engineering B-Solid State Materials for Advanced Technology, 2002) Plaza, J. L.; Hidalgo Alcalde, Pedro; Méndez Martín, Bianchi; Piqueras de Noriega, Javier; Dieguez, E.
The defect structure of Te-doped GaSb samples co-doped with Er_2O_3 and grown by the vertical Bridgman technique has been analysed. This study was carried out for different Er and Te concentrations. The defect structure of the samples has been analysed by means of cathodoluminescence (CL), scanning electron microscopy (SEM) and wavelength dispersive X-ray microanalysis (WDX). The effect of the defect structure and sample composition on the electrical properties of the material has been established taking into account the results obtained by means of the van der Pauw technique.
Estudio de la incorporación de iones de Er y Nd en galio antimonio crecido por el método Bridgman
(Boletín de la Sociedad Española de Cerámica y Vidrio, 2000) Plaza, J. L.; Hidalgo Alcalde, Pedro; Piqueras de Noriega, Javier; Dieguez, E.
En 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 efectivo de ambos dopantes a lo largo de la dirección de crecimiento del material. Mediante medidas de efecto Hall se ha determinado el tipo de portadores mayoritarios (huecos) así como los valores de la movilidad, la densidad de portadores y la resistividad para cada una de las concentraciones. Los análisis de dispersión de energías de rayos X (EDAX) y de microscopio electrónico de barrido (SEM) han demostrado la presencia de agregados formados por los iones de tierras raras y Sb para las concentraciones de dopante más altas. La reducción de los defectos nativos tales como las vacantes de Ga y Ga en posición de Sb por los iones de Er ha sido también demostrado a través de análisis de catodoluminiscencia.
Surface characterisation and cathodoluminescent response of nanodot-patterned GaSb surfaces by low energy ion sputtering
(Journal of Physics: Conference Series, 2007) Plaza, J. L.; Hidalgo Alcalde, Pedro; Diéguez, E.
The scope of this paper is to analyse the effect of Au and Cr impurities, diffused onto GaSb substrates on the formation of nanodots created by LEIS using Ar+ ions It is concluded that oblique incidence in rotating configuration delays the formation of the nanodots compared to previously reported normal incidence experiments. The presence of cracks induced by the sputtering process has been observed both in the Au and Cr diffused samples. Cathodoluminescence (CL) spectra obtained in irradiated samples both pure and Cr-diffused have revealed no difference between them, showing the usual three band encountered in this material (Band Gap at 798 meV, A Band at 777 meV and tail-states at 815 meV). However, a fourth band has been detected in the Au sample centered at 769 meV.
Polishing, chemical etching and thermal treatment effects on surface and electrical properties of Er and Nd-doped GaSb substrates
(Materials Science and Engineering B-Solid State Materials for Advanced Technology, 2000) Plaza, J. L.; Hidalgo Alcalde, Pedro; Méndez Martín, Bianchi; Piqueras de Noriega, Javier; Dieguez, E.
In this work several changes induced by polishing, chemical etching and thermal treatment in the properties of Er- and Nd-doped GaSb substrates with different doping levels grown by the vertical Bridgman method have been studied. The analysis has revealed the formation of precipitates at the highest doping levels for both Er- and Nd-doped GaSb. Cathodoluminescence analysis shows the reduction of the defect band induced by the rare earth (RE) elements. For high dopant concentrations the precipitation phenomena reduce this effect. Thermal treatments have produced an enhancement of the p-type properties of the samples. For a dopant density of 2 x 10(19) cm(-3) this effect is more pronounced.
Cathodoluminescence from Er_2O_3-doped n-type GaSb : Te crystals
(Journal of Physics: Condensed Mater, 2002) Hidalgo Alcalde, Pedro; Plaza, J. L.; Méndez Martín, Bianchi; Dieguez, E.; Piqueras de Noriega, Javier
The luminescence of Te-doped GaSb crystals codoped with Er2O3 has been studied by means of cathodoluminescene (CL) using a scanning electron microscope. Doping with erbium oxide causes a substantial increase of the luminescence intensity of the crystals and spectral broadening. Deconvolution of the CL spectra reveals the existence of four components. The presence of erbium oxide induces a decrease of the 746 meV emission characteristic of Te-doped samples. CL images show a complex distribution of recombination centres which depends to a large extent on he local Te concentration.
Effect of Er dopant in GaSb bulk crystals grown by vertical Bridgman technique
(Journal of crystal growthJ, 1999) Plaza, J. L.; Hidalgo Alcalde, Pedro; Méndez Martín, Bianchi; Piqueras de Noriega, Javier; Castaño, J. L.; Dieguez, E.
The 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 incorporation of Er at subgrain boundaries has been shown by cathodoluminescence studies.
Effect of erbium on the luminescence properties of GaSb crystals
(Solid State Phenomena, 1998) Hidalgo Alcalde, Pedro; Méndez Martín, Bianchi; Piqueras de Noriega, Javier; Plaza, J. L.; Diéguez, E.
The 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 independent rare-earth luminescence and the possibility of activation of the emitting rare-earth centers by minority carrier injection. In this work the effect of erbium doping on the luminescence and on the native accepters of GaSb crystals has been investigated by CL-SEM. Er doping has been found to increase the total CL intensity and to produce spectral changes that depend on the erbium concentration. At moderate doping the native acceptor concentration, as detected by the luminescence band A, decreases. At high Er concentrations Er-Sb precipitates form and doping appears not to be efficient in the suppression of accepters. X-ray microanalysis reveals that the composition of the precipitates is Er-5 Sb-3. Emission from intraionic transitions of Er is observed in highly doped crystals.