A model for conductance in n-type non-degenerate semiconductors is proposed and applied to polycrystalline SnO2 used as a gas sensor. Particular attention is devoted to the fundamental mechanism of Schottky barrier formation due to surface states in nanostructured grains. Electrical and absorption infra-red spectroscopic analysis constitutes strong evidence for oxygen diffusion into the tin oxide grains. The model is then extended to include oxygen in- and out-diffusion. Thus, it is possible to explain the long-term resistance drift in oxygen for fully depleted grained samples in terms of tunneling through the double barrier.
Electrical and spectroscopic analysis in nanostructured SnO2: "Long-term" resistance drift is due to in-diffusion
MALAGU', Cesare;GIBERTI, Alessio;
2011
Abstract
A model for conductance in n-type non-degenerate semiconductors is proposed and applied to polycrystalline SnO2 used as a gas sensor. Particular attention is devoted to the fundamental mechanism of Schottky barrier formation due to surface states in nanostructured grains. Electrical and absorption infra-red spectroscopic analysis constitutes strong evidence for oxygen diffusion into the tin oxide grains. The model is then extended to include oxygen in- and out-diffusion. Thus, it is possible to explain the long-term resistance drift in oxygen for fully depleted grained samples in terms of tunneling through the double barrier.File in questo prodotto:
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