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© 2007 IOP Publishing Ltd. This work has been supported by the Ministry of Education and Science of Spain under a Ramon y Cajal Contract, by the project MAT2003-09873 and by the project MEC (MAT 2003-00455)., The luminescence of porous InP prepared by electrochemical etching is investigated by cathodoluminescence (CL) in a scanning electron microscope (SEM). Anodization causes a strong reduction of CL intensity as well as a blue spectral shift. Additional blue shift and enhancement of CL intensity is observed in samples cracked in vacuum by the effect of the SEM electron beam, which is explained by the reduction of the influence of surface states on the recombination mechanism. The relationship of the CL spatial distribution with the multilayer porous structure is described., España. Ministerio de Educación y Ciencia, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 2009 IOP Publishing Ltd. This work was supported by MEC (Project MAT2006-01259)., Bi doped ZnO nanowires and rods have been grown by a catalyst free evaporation-deposition method with precursors containing either ZnO and Bi_2O_3 or ZnS and Bi_2O_3 powders. The use of ZnS as a precursor was found to lead to a higher density of nano- and microstructures at lower temperatures than by using ZnO. Energy dispersive x-ray spectroscopy (EDS) shows that the Bi content in the wires and rods is in the range 0.15-0.35 at%. Bi incorporation was found to induce a red shift of the near band gap luminescence but no quantitative correlation between the shift and the amount of Bi, as measured by EDS, was observed. The I-V curves of single Bi doped wires had linear behaviour at low current and non-linear behaviour for high currents, qualitatively similar to that of undoped wires., MEC, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 2007 IOP Publishing Ltd. International Conference on Nanoscience and Technology (2006.Basel, Switzerland ). This work has been supported by the Ministry of Education and Science of Spain under a Ramon y Cajal Contract, by the project MAT2003-09873 and by the project MEC (MAT 2003-00455), 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., Ministry of Education and Science of Spain, MEC, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 1999 IOP Publishing Ltd. This work has been supported by the DGES (project No PB96-0639) and CICYT (projects ESP95-0148 and ESP98-1340)., The 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 concentration in contrast to what occurs with other isoelectronic dopants (e.g. aluminium). Large In concentrations lead to the formation of the ternary compound In_xGa_(1-x)Sb as revealed by CL spectra and x-ray measurements. In particular, a luminescence band and x-ray diffraction peaks observed in highly doped samples are attributed to the presence of In_xGa_(1-x)Sb., DGES, CICYT, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 2008 IOP Publishing Ltd. This work was supported by MEC (Project MAT2006-01259)., Sn doped GeO_2 nanowires and microwires have been grown by an evaporation-deposition method, using a mixture of Ge and SnO_2 powders as precursors. Comparison with undoped GeO_2 nanowires grown by the same method shows that the presence of Sn prevents the formation of sharp bends, which makes the wires more suitable for waveguiding applications. Incorporation of about 0.5 at.% of Sn into the wires influences their morphology and gives rise to wires showing two different cross-sectional dimensions along the growth axis. Sn does not influence the luminescence spectra in the visible range but causes the appearance of emission bands in the near-infrared range. The waveguiding behavior of the Sn doped wires for green and red laser light has been demonstrated., MEC, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 1998 IOP Publishing Ltd. This work has been supported by DGES (PB96-0639) and by CICYT (ESP95-0148 and 95-0086-OP)., GaSb 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 concentrations, Er-Sb precipitates form and doping becomes less efficient in suppressing the accepters. In these samples intraionic Er luminescence is observed., DGES, CICYT, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 2007 IOP Publishing Ltd. This work has been supported by MEC (Project MAT2003-00455) and UCM-CM (Group 910146)., High aspect ratio GeO_2 nano- and microwires have been grown by thermal treatment at 600 degrees C of compacted Ge powder under argon flow. The wires have cross-sectional dimensions from less than 100 nm to about 1 mu m, depending on the duration of the treatment, and lengths of up to about 2000 mu m. Waveguide behaviour of the wires was demonstrated for visible light, which shows the potential applications of these structures for optical nanodevices., MEC, UCM-CM, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 2005 IOP Publishing Ltd. This work was supported by MEC (Project MAT 2003-00455) and CAM (Project GR/MAT 630-04)., Thermal 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 nanoneedles. Enhanced cathodoluminescence emission is associated with the wires and needles, which show a component at 2.72 eV not observed. for the untreated material., MEC, CAM, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 2004 IOP Publishing Ltd. International Workshop on Beam Injection Assessment of Microstructures in Semconductors. (7. 2003. Lille. Francia). This work was sponsored by CNRS/ADEME (France), by Conseils Regional (PACA) and General (13)-France and by Secretaria General Educacion y Universidades (Spain)., By means of a contactless microwave phase shift technique, the minority carrier lifetime and surface recombination velocity were measured in multicrystalline silicon wafers containing iron and chromium. The bulk lifetime can be deduced, leading to the determination of the concentration of interstitial iron [Fe-i] associated with boron, after pair dissociation annealing at 210 degreesC. It is found that [Fe-i] is higher in the vicinity of extended defects but decreases at the defects because the iron segregates irrespective of boron concentration and does not form pairs., CNRS/ADEME (France), Conseils Regional (PACA), General (13)-France, Secretaria General Educacion y Universidades (Spain)., Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

Cathodoluminescence (CL) in the scanning electron microscope (SEM) has been used to investigate the effect of doping with chromium and vanadium on the native accepters and on the general structure of extended defects of gallium antimonide single crystals. Both impurities cause the reduction of the CL band at 775 meV (band A) attributed to a native acceptor. This effect is explained by the formation of a complex involving the dopant. CL images reveal the presence of precipitates and inhomogeneities in impurity distribution.