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Lookup NU author(s): Dr Alton Horsfall,
Dr Ming-Hung Weng,
Dr Rajat Mahapatra,
Professor Nick Wright
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We present the variation of trap assisted conduction current through a dielectric stack comprising TiO2 and SiO2 on SiC as a function of both temperature and hydrogen gas concentration. We show that the current can be modeled by the use of a single barrier height across the temperature range of interest (>300°C ambient). Upon exposure to hydrogen gas, this barrier height is reduced from 0.405 to 0.325eV, whilst the density of traps in the bulk of the TiO2 remains unaffected. We conclude that the formation of a charge dipole layer under the palladium contact is responsible for this change in barrier height, as has been observed in Schottky diode sensor structures. Further, sensing the gas concentration by monitoring of the trap assisted conduction current appears not to be influenced by the existence of interfacial traps, offering the chance to fabricate low drift sensors for deployment in extreme environments.
Author(s): Horsfall AB, Weng M-H, Mahapatra R, Wright NG
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: 6th European Conference on Silicon Carbide and Related Materials (ECSCRM 2006)
Year of Conference: 2007
Publisher: Materials Science Forum: Trans Tech Publications Ltd
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