Electro-optical properties of Er-doped SnO2 thin films

Photo-Induced conductivity of heterojunction GaAs/Rare-Earth doped SnO2

“…At 190 K, both light sources with energy below the SnO 2 bandgap, yields negligible effects on the conductivity. This result is in good agreement with the results shown in Figure 3, where the light effects on the GaAs shield are evident only below 100 K. Concerning the effect of the Nd:YAG laser on the sample, it is due to the persistent photoconductivity phenomena 32 . In this case, the capture of photoexcited electrons certainly evolves into a lattice relaxation process, where the electron trapping over a capture barrier is a thermally activated process.…”

Optical excitation of charge carriers from intra-bandgap states in Ce-doped SnO[sub 2] thin films

“…In order to investigate electroluminescent characteristics of Ce 3+ -doped SnO 2 thin films, the optical ionization of Ce-related defects and the analysis of charge trapping back may become a very important tool, since it combines optical and electrical properties of Ce-doped SnO 2 thin films. Ce 3+ is incorporated into SnO 2 lattice substitutional in Sn 4+ sites and exhibits an acceptor like behavior in tin dioxide [7], leading to a high degree of electrical charge compensation, and high resistivity films. Recombination of electron-hole pairs with desorbed oxygen species leads to persistent photoconductivity (PPC) effect [8] in undoped SnO 2 sol-gel thin films at low temperature [7], and to an exponentiallike decay for RE-doped SnO 2 .…”

“…Ce 3+ is incorporated into SnO 2 lattice substitutional in Sn 4+ sites and exhibits an acceptor like behavior in tin dioxide [7], leading to a high degree of electrical charge compensation, and high resistivity films. Recombination of electron-hole pairs with desorbed oxygen species leads to persistent photoconductivity (PPC) effect [8] in undoped SnO 2 sol-gel thin films at low temperature [7], and to an exponentiallike decay for RE-doped SnO 2 . The decay of photo-excited conductivity can be applied in order to understand the electron trapping phenomena [9].…”

“…After removing the illumination, the time-temperature dependence of charge carrier trapping by defects is measured and the thermally activated capture cross section of the dominating level is evaluated. Recently, the decay of excited conductivity of Er-doped SnO 2 have been recorded and the carrier trapping by Er-related defects have been modeled [7,9], where the excitation is obtained with the fourth harmonic of a Nd:YAG laser (266nm), which leads to ionization of intra-bandgap defect centers along with electron-hole pairs.…”

Investigação de propriedades de filmes finos de Sn'O IND. 2' e 'Al IND. 2''O IND. 3' para aplicação em dispositivos

“…Essa resistividade é mais baixa do que a mesma medida feita em ar (Tabela 2), o que deve estar relacionado com a diminuição de oxigênio adsorvido na matriz. Como descrito por outros autores (Yamazone et.al., 1979;Morais et.al., 2004), a adsorção de gás oxigênio aumenta a resistividade do material, devido à captura de elétrons da rede quando o oxigênio é (Redecka, Zakrzewska, Mieczyslaw, 1998 Possivelmente, a mudança na estrutura interfacial, devido ao aumento de NH 4 OH, ajude na difusão do contato no semicondutor.…”