L. Boarino et al., Towards a deeper comprehension of the interaction mechanisms between mesoporous silicon and NO2, PHYS ST S-A, 182(1), 2000, pp. 465-471
The high sensitivity of a room-temperature porous silicon NO2 sensor has re
quired an investigation of surface dynamics between NO2 and mesoporous sili
con. By means of electrical measurements in gas atmosphere and in-situ FTIR
, evidence of a new interaction mechanism strongly affecting the electrical
conductivity of the porous silicon (PS) sensors has been found. Absorption
bands have been attributed to NO2-, suggesting carrier transfer from the s
ilicon wires to NO2, thanks to its high electronic affinity. The models pro
posed until now, explaining the high resistivity of mesoporous silicon, str
ongly support this interpretation.