A theoretical model has been developed to interpret the different behavior of SnO2 and TiO2 sensors. It is based on the determination of the surface-state density, which pins the Fermi level of the semiconductor, thus removing the linear relationship between the work function and the grain-to-grain energy barrier. To interpret these differences, measurements of the built-in potential Vbi, related to the Schottky barrier, were pursued at different temperatures in thick films of SnO2 and TiO2, obtained via sol-gel. The model predicts a decrease in the density of surface states with the grain radius only in TiO2, which seems to be confirmed by experiment.
Model for the density of surface states and the Schottky barrier height in SnO2 and TiO2 thick film gas sensors
MALAGU', Cesare;CAROTTA, Maria Cristina;GIBERTI, Alessio;GUIDI, Vincenzo;
2004
Abstract
A theoretical model has been developed to interpret the different behavior of SnO2 and TiO2 sensors. It is based on the determination of the surface-state density, which pins the Fermi level of the semiconductor, thus removing the linear relationship between the work function and the grain-to-grain energy barrier. To interpret these differences, measurements of the built-in potential Vbi, related to the Schottky barrier, were pursued at different temperatures in thick films of SnO2 and TiO2, obtained via sol-gel. The model predicts a decrease in the density of surface states with the grain radius only in TiO2, which seems to be confirmed by experiment.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
