Porous silicon (PS), obtained by electrochemical anodization of an n-type s
ilicon wafer, was catalysed by sputtering gold onto the surface (4, 8, 15 a
nd 40-nm nominal thickness). Investigation by Rutherford backscattering spe
ctroscopy (RBS) and by electron microscopy showed that gold did not form a
continuous layer, but rather formed clusters penetrating into the ports of
PS by about 1 mu m. A variation of the sample conductivity in the presence
of a few parts per million of NO, and NO was recorded at room temperature.
We demonstrated that, as a result of Au catalysation, PS is suitable for se
nsing nitrogen oxides with negligible influence by interfering gases such a
s CO, CH, or methanol. Indeed, we found that humidity appreciably affected
the response. (C) 2000 Elsevier Science S.A. All rights reserved.