Z. Gaburro et al., Monitoring penetration of ethanol in a porous silicon microcavity by photoluminescence interferometry, APPL PHYS L, 78(23), 2001, pp. 3744-3746
A photoluminescent porous silicon microcavity is exposed to saturated vapor
of ethanol. The ethanol substitutes the air inside the pores giving rise t
o a progressive monotonic redshift of the interference pattern of the photo
luminescence spectrum. On the other hand, the photoluminescence intensity o
f the cavity peak oscillates in time. Both effects can be explained in term
s of a very simple model based on the progressive change of the effective r
efractive index of single layers of the cavity. The change is due to the di
fference between the index of refraction of air and ethanol. The result sug
gests that a porous silicon microcavity can be a tool to study the dynamics
of gas penetration into porous silicon since it allows a monitoring of the
depth reached by the ethanol at any given time. (C) 2001 American Institut
e of Physics.