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Abstract. Transparent conducting thin films of aluminum-doped zinc oxide (ZnO:Al) have been deposited on SnO 2 :F/glass by the chemical spray technique, starting from zinc acetate (CH 3 CO 2 ) 2 Zn.2H 2 O and aluminum chloride AlCl 3 . The effect of changing the aluminum-to-zinc ratio y from 0 to 3 at.%, has been thoroughly investigated. It was found that the optical and electrical properties of Al doped ZnO films improved with the addition of aluminum in the spray solution until y=2%. At this Al doping percentage, the thin layers have a resistivity equal to 4.1 x 10 -4 Ω.cm and a transmittance of about 90 % in the region [600-1000] nm. XRD patterns confirm that the films have polycristalline nature and a wurtzite (hexagonal) structure which characterized with (100), (002) and (101) principal orientations. The undoped films have (002) as the preferred orientation but Al doped ones have (101) as the preferred orientation. Beyond y= 1%, peak intensities decrease considerably.

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CuInS 2 and CuIn(1−x)AlxS2 thin films have been deposited on different substrates using the spray pyrolysis technique at 320 °C. X-ray diffraction, atomic force microscopy, and scanning electron microscopy were used to characterize the structure of the films; the surface compositions of the films were studied by Auger electrons spectroscopy and energy dispersive 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, its surface morphology, and the introduction of small amounts of Al in the layer on the properties of the films. The best crystallized composition of CuInS2 was obtained for deposits on pyrex. This was improved by the introduction of Al atoms. The work function differences (φmaterial−φprobe) for CuInS2 and CuIn(1−x)AlxS2 deposited on pyrex were equal to −350 meV and to −400 meV, respectively. Putting Al atoms in the film increases φm (by about 50 meV) and induces the formation of a negative surface barrier. The best composition was obtained for CuInS2 deposited on SnO2 and annealed. Auger studies shows that the concentration of S and C elements increased when the samples were annealed under a vacuum, whereas the concentration of Cu, In, and O decreased. In the case of CuInS2 grown on pyrex, the introduction of Al increases the O, S, and Cl concentrations and reduces Cu and C concentrations. Analysis of the film compositions by EDS gives the following concentrations [Cu]=24.270%, [In]=24.487%, [S]=46.670%, and [Cl]=4.573%.

Photothermal deflection spectroscopy (PDS) is carried out in order to investigate thermal and optical properties of Al doped In2S3. The influence of thermal annealing on its gap energy as well as its thermal properties is revealed. In this way, we notice that thermal conductivity is increased and the gap energy is reduced. These features are probably due to the improvement of the crystalline structure of the sample.

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