Universidad Nacional Autónoma de México - CNyN

1st International Symposium on Nanoscience and Nanomaterials
occurs around 400 K, as the copper atoms become reduced to a metallic state, to form acetonitrile and a secbutylamido
surface species that reacts further at 485 K to release 2-butene, and by 800 K, only copper and a
small amount of carbon can be seen on the surface by XPS. A temperature window between approximately
350 and 450 K was identified for the clean deposition of the precursor on the surface: lower temperatures are
insufficient for activation of the dissociative adsorption, and higher temperatures lead to continuous
decomposition beyond Cu monolayer saturation.
PLENARY III
SYNTHESIS AND PROPERTIES OF SMALL DIMENSIONAL STRUCTURES OF TRANSPARENT
CONDUCTING OXIDES.
Ana Cremades 1,a , D. Maestre 1,b , Javier Bartolomé 1,c , Cristian Vásquez 1,d , Manuel Herrera 2,e and J. Piqueras 1,f .
1 Departamento de Física de Materiales, Facultad de Físicas, Universidad Complutense de Madrid, 28040
Madrid, Spain
2 Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, México
a cremades@fis.ucm.es, b davidmaestre@fis.ucm.es , c j.bartolome@fis.ucm.es, d gc.vasquezv@pas.ucm.es, e
zaldivar@cnyn.unam.mx , f piqueras@fis.ucm.es
Keywords: TCO Nanostructures, Vapor-solid growth, Doping, Luminescence
Indium, tin and titanium oxides are extensively investigated transparent conducting oxide materials
with relevant technological applications in many fields, such as optoelectronic devices, solar cells, field
emitters, or gas sensors. Recently, the synthesis and characterization of undoped and doped nano- and
microstructures of these materials in forms of nanowires, nanorods, nanopyramids, or nanoarrows have
attracted increasing attention, as the exploitation of the phenomena appearing at the nanoscale could spread
their applications as nanoelectronic and optoelectronic devices. However, although a reasonable control of the
growth of nanostructures has been achieved, some relevant issues related to the growth mechanism are still
open. Anisotropic growth, defect-induced growth, self catalytic growth, and oxide assisted growth have been
suggested to be the driven forces of nanowire growth by the VS process. Recently, a dislocation driven
growth mechanism has been proposed for indium oxide, indium tin oxide (ITO) nanostructures 1,2 and zinc
doped indium oxide 3 . Effective or limited doping incorporation is another aspect directly related to the control
of properties of interest for applications as luminescence, guide lighting behavior, and field emission. Beside,
the adsorption of doping atoms to the surfaces of the growing nanostructures may cause inhibition of the
crystalline growth as observed for Mn doped In 2 O 3 4 or SnO 2 5 , or even phase transformation of the host lattice 6
as for V doped TiO 2 ,or ternary formation 3 as for Zn doped In 2 O 3 or Er doped SnO 2 . This contribution
elucidates some of the former aspects for doped In 2 O 3 , SnO 2 and TiO 2 micro- and nanostructures grown by an
evaporation-solidification method. The relationship between their structure and the electronic and optical
properties as a function of the doping, with elements such as rare earths, transition metals, Sn or Zn, has been
investigated. The structure has been characterized by SEM and TEM and the chemical analysis have been
performed by means of energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Imaging and
spectral cathodoluminescence have been used for the luminescence analysis.
1D . Maestre et al. Crystal growth and design 11, 1117 – 1121 (2011)
2D . Maestre et al. J. Phys. Chem. C 115, 18083-18087, (2011)
3J . Bartolomé et al. J.Phys.Chem.C 115, 8354-8360, (2011)
2