Otro
Optical excitation of charge carriers from intra-bandgap states in Ce-doped SnO2 thin films
Registro en:
AIP Conference Proceedings, v. 992, p. 1283-1288.
0094-243X
1551-7616
10.1063/1.2926834
WOS:000255857900226
2-s2.0-43649091184.pdf
2-s2.0-43649091184
Autor
Silva, Vitor D. L.
Pineiz, Tatiane F.
Morais, Evandro A.
Pinheiro, Marco A. L.
Scalvi, Luis Vicente de Andrade
Saeki, Margarida Juri
Rubo, Elisabete Aparecida Andrello
Resumen
Optical excitation of Ce3+-doped SnO2 thin films, obtained by the sol-gel-dip-coating technique, is carried out and the effects on electrical transport are evaluated. Samples are doped with O. lat% of Ce, just above the saturation limit. The excitation is done with an intensity-controlled halogen-tungsten lamp through an interference filter, yielding an excitation wavelength of 513nm, 9 nm wide (width at half intensity peak). Irradiation at low temperature (25K) yields a conductivity increase much lower than above bandgap light. Such a behavior assures the ionization of intra-bandgap defect levels, since the filter does not allow excitation of electron-hole pairs, what would happen only in the UV range (below about 350nm). The decay of intra-bandgap excited levels in the range 250-320 K is recorded, leading to a temperature dependent behavior related to a thermally excited capture cross section for the dominating defect level. © 2008 American Institute of Physics.