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Role of microstructure and layer thickness in porous silicon conductometric gas sensors
Author(s) -
Gaburro Z.,
Oton C. J.,
Ghulinyan M.,
Pancheri L.,
Pavesi L.,
Capuj N.
Publication year - 2005
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200461138
Subject(s) - microstructure , materials science , porosity , silicon , porous silicon , doping , composite material , branching (polymer chemistry) , layer (electronics) , morphology (biology) , optoelectronics , biology , genetics
The electrical injection in porous silicon fabricated with heavily doped p‐type silicon is very sensitive to NO 2 . The known effect is an injection increase associated to NO 2 . We show experimentally a strong correlation between two structural properties and the sensitivity of electrical injection to NO 2 . The first property is the microstructure, i.e. the pore morphology at nm scale. A structure with straight, elongated pores shows large sensitivity, as opposed to a branching structure. The second property is the layer thickness, which determines the sign of the effect of NO 2 . If the thickness is sufficiently low – of the order of few µm – the injection in presence of NO 2 decreases, instead of increasing. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)