beta -In2S3 and beta -In2-xAlxS3 thin films have been deposited on differen
t substrates using the spray pyrolysis technique at 320 degreesC. X-ray dif
fraction, atomic force microscopy, and scanning electron microscopy were us
ed to characterize the structure of the films; the surface compositions of
the films were studied by Auger electrons spectroscopy and energy dispersiv
e spectrometry (EDS), the work function and the photovoltage by the Kelvin
method. Using these techniques, we have specified the effect of the nature
of the substrate, of its surface morphology, of the introduction of small a
mounts of Al in the layer, on the properties of the films. The best crystal
lized of beta -In2S3 were obtained for deposits on pyrex. This was improved
by the introduction of Al atoms. The work function differences (phi (mater
ial)-phi (probe)) for beta -In2S3 and beta -In2-xAlxS3 deposited on steel w
ere equal to -150 meV and to -180 meV, respectively. Putting Al atoms in th
e film increases phi (m) (by about 30 meV) and induces the formation of a n
egative surface barrier. The concentration of In, S, and O elements increas
ed when the samples were annealed under a vacuum, whereas the concentration
of carbon decreased. The best composition was obtained for In2S3 deposited
on SnO2 and annealed. The introduction of Al increases O and C concentrati
ons and reduce In, Cl, and S concentrations. Analysis of the film compositi
ons by EDS gives the following concentrations [In]=37%, [S]=52%, and [Cl]=1
1%. (C) 2001 American Institute of Physics.