Chalcogenisation of Cu-Sb metallic precursors for thin film photovoltaic devices

In this paper, we report on the sulphurisation/selenisation of CuSb metallic precursors. The precursors were deposited by magnetron sputtering on molybdenum coated glass substrates from elemental targets. They were coated with an evaporated Se and/or S layer before annealing in a tube furnace at temperature of 500 °C. The thickness of the Se and S layers was adjusted to yield a range of compositions. The films were characterised by X-ray diffraction, secondary electron microscopy, secondary ion mass spectroscopy and photoelectrochemical measurements. Se-free films deposited on molybdenum/glass crystallised into Cu3SbS3 with a monoclinic structure. Chalcogenides converted at 500 °C showed p-type conductivity and energy band gaps varying from 1.2eV to 1.8eV depending on the S/Se ratio. Quantum efficiency curves were recorded over the spectral range 400-1300nm using a 3-electrode configuration in aqueous Eu(NO3)3. The measurements indicate that the films fabricated are photoactive and active junctions are formed.