Doped Bi-Se thin films for photovoltaic applications

Cu_xBi_ySe_z thin films with copper concentration x up to 29 mol. % are synthesized on glass substrates by chemical-bath deposition. Films with thickness in the range of 550-597 nm are fabricated by a multiple-dip process. Deposition parameters for a single-coating run are optimized to avoid re-dissolution of the particles, and to obtain large-area composition homogeneity in the films. Routine film composition Cu:Bi:Se and thickness are analyzed by X-ray fluorescence. To evaluate the doped Bi-Se thin films for potential use in photovoltaic devices, systematic investigations of the films´ structural, morphological, optical, and electrical properties are performed. The physical properties of as-deposited and annealed films are analyzed by X-ray diffraction, scanning electron microscopy, UV-Vis-IR photospectroscopy, and Hall effect and Seebeck effect measurements.