Structures confining light along one or two directions (microcavities) are
of prime importance for the construction of opto-electronic devices based o
n luminescent semiconductor materials. Our work is devoted to the making of
microcavities centered at 2.4 eV (515 nm) formed by two TiO2/SiO2 distribu
ted Bragg reflectors, surrounding an emitting layer. The emitting layer is
an organic semiconductor (trihydroxyquinoline-aluminum, Alq(3)) chosen for
its strong luminescent efficiency. For the fabrication of such complex stru
cture, the layer optical path length is an determining parameter to obtain
a high quality microcavity. First, a particular attention has been paid to
the characterization of the optical properties of the active layer and the
mirror layers. Optical indices have been obtained by means of spectroellips
ometry. Alq(3) and TiO2 dispersion laws were successfully modeled with a mo
del developed by Forohoui and Bloomer. Secondly, we applied in situ ellipso
metry to control the mirror layer deposition. Finally, we show that this me
thod allows microcavity fabrication with good accuracy. (C) 2000 Elsevier S
cience S.A. All rights reserved.