Contribution à l’amélioration des performances des cellules solaires CuIn1-xGaxSe2

Abstract

The recent development of photovoltaic structures is at the origin of numerous studies currently being undertaken on thin film solar cells based on Cu(In,Ga)Se2 (CIGS) compounds. In this important technological context, our choice has carried, in a first step, by numerical modeling study of the original superstrate solar cell based on CIGS thin films polycrystalline absorbers from AMPS-1D simulator tool. The modeling allowed us to access in the most important parameters for the proper functioning of a superstrate-type solar cell Zn/In2Se3/CIGS/SnO2:F/SLG. This considering the atomic diffusion of chemical elements that occurs in the structure. In a second step we have a process to elaborate large spaced CIGS thin film solar cells by a technique not expensive and not widely known in the development of CIGS absorbers : rf-magnetron sputtering. The CIGS films deposition were performed at different substrate temperature and were annealed under Argon atmosphere at various annealing for one hour. The as-deposited films are submitted to a series of structural, , optical and electrical . The effect of the substrate temperature and annealing on the layer properties were studied. The surface morphology observed shows that the films are very homogeneous and the roughness increases with increasing substrate temperature. The EDS measurements revealed that the compositions very close to the stoichiometry. The diffraction peaks observed of the material correspond to the chalcopyrite structure. The films resistivity increases with increasing deposition temperature. It is varied between 10 and 180 Ω.cm. measurements were determined and the as a function of incident photon energy of the layers were obtained. The optical gap values are varied between 1.13 and 1.22 eV. These results respond favorably to the photovoltaic conversion criteria for producing solar cells based on CIGS absorbers.