Universidad Nacional Autónoma de México - CNyN

1st International Symposium on Nanoscience and Nanomaterials
a noejd@cnyn.unam.mx, b gilotanez@cnyn.unam.mx, c trino@cnyn.unam.mx, d sergio@cnyn.unam.mx,
e vitalii@cnyn.unam.mx
Keywords: Mesoporous, surfactants, templates, alumina, HDS.
Significant efforts were dedicated to synthesis of nanostructured alumina with a unimodal pore size
distribution. However, the production of ordered and thermally stable mesoporous alumina represents a much
more difficult problem due to its susceptibility for hydrolysis as well as to the phase transitions accompanying
the thermal breakdown of the ordered structure [1]. Unfortunately till now disordered structures with
amorphous walls were fabricated in most cases [2]. In this work, in order to obtain alumina supports for
hydrodesulphurization (HDS), the synthesis of bulk materials were carried out using typical precursors and
surfactants as structure directing agents. The alumina supports were characterized by physisorption of N 2 ,
small and wide angle XRD, SEM and HRTEM. The preliminary results showed large surface area, tunable
and narrow pore size distribution. Obtained materials have interesting textural properties for the preparation
of HDS catalyst. However, additional characterizations that are in progress are required to conclude usability
of the obtained materials. The technical support provided by M. E. Aparicio, I. Gradilla and F. Ruiz is
acknowledged. This work was supported by CONACyT-SENER Project 117373.
[1] Cejka et al., J. Appl. Catal. A. 254 (2003) 327.
[2] Quan Y. et al., J. Am. Chem. Soc. 130 (2008) 3465.
O-015
SYNTHESIS AND CATHODOLUMINESCENCE OF SEMICONDUCTOR NANOWIRES WITH
WIDE BAND-GAP
G. Guzmán 1 , A. Guerrero 2 , M. Herrera 3,a , D. Maestre 4 and J. Valenzuela 3 .
1 Posgrado en Ciencias Físicas, Universidad Nacional Autónoma de México, Ensenada, Baja California 22800,
México.
2 Posgrado en Ciencia e Ingeniería de Materiales, Universidad Nacional Autónoma de México, Ensenada, Baja
California, México.
3 Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Baja
California 22800, México.
4 Departamento de Física de Materiales, Universidad Complutense de Madrid, Madrid 28040, Spain.
a zaldivar@cnyn.unam.mx
Keywords: gallium oxide, GaN, ZnO, nanowires, cathodoluminescence.
Nanowires of β-Ga 2 O 3 and GaN have been synthesized by physical vapor deposition (PVD) onto
several substrates and at different temperatures to study their optical properties by cathodoluminescence (CL).
β-Ga 2 O 3 nanowires were synthesized onto Si(100) and show a self-catalyzed growth generated by the
formation of metallic gallium. Thermal diffusion of Ga 0 on the substrate generated formation of stacking
faults in the nanowires, which were identified as dark regions in the CL images. CL spectra from β-
Ga 2 O 3 /Si(100) recorded a strong UV emission (3.3 eV), while the nanowires grown onto Au/Si(100) show a
weak blue emission (2.8 eV). The UV emission was assigned to self-trapped excitons and the blue band to a
donor-acceptor transition. 1 GaN nanotubes were grown by PVD onto Au/Si(100) using a flow of NH 3 to
generated a nitridation of gallium oxide. CL measurements show the defect-related yellow emission (2.3 eV)
at 300 K, and the GaN band-edge emission at 100 K. ZnO:Mn nanowires synthesized by the hydrothermal
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