Structural and Morphological studies of CuIn(1−x)AlxS2 deposited by spray on various substrates

Abstract

Abstract Structural properties of CuIn (1− x ) Al x S 2 layers obtained by spray pyrolysis on various substrates were studied using X Ray Diffraction, Atomic Force Microscopy and Scanning electron microscopy. The concentration of Al in the spray solution, represented by the ratio z ( z = [ Al 3 + ] / [ In 3 + ] ), was varied from 0 to 3.2%. The different substrates are: glass, ZnO/glass, SnO 2 /glass, ZnO/SnO 2 /glass and In 2 S 3 /Glass. All the layers were deposited by spray. The ZnO used in the substrates was doped with indium. The concentration of indium in the ZnO sprayed solution is [In]/[Zn]=3%. The X-ray diffraction spectra revealed that, different values of the ratio z, the CuIn (1− x ) Al x S 2 thin films were well crystallized in the tetragonal structure of the CuInS 2 material with the privileged orientation (112) whatever the substrate. The surface topography of the CuIn (1− x ) Al x S 2 thin films, deduced from the Atomic Force Microscopy, proved that the grain size in the top of the layers depends both on the z value and on the substrate. The Auger analysis has been done in order to get information on the surface layer composition, the measurement show that the surface chemical composition where improved by annealing. In this work the performances of the solar cell CuIn (1− x ) Al x S 2 (p)/CuInS 2 (p)/In 2 S 3 (n)/ZnO, realized with optimized value of Al concentration, is also presented.