An investigation on palladium sulphide (PdS) thin films as a photovoltaic material

Polycrystalline PdS thin films with tetragonal structure have been grown by direct sulphuration of Pd layers. They are formed by crystallites of size ∼ 50 nm. As-grown PdS films show a Seebeck coefficient, S = − 250 ± 30 μV/K, which indicates an n-type conductivity. Electrical resistivity of the samples, measured by the four contact probe, is (6.0 ± 0.6) × 10− 2 Ω·cm. Hall effect measurements, confirms n-type conductivity with a negative carrier density n = (8.0 ± 2.0) × 1018 cm− 3 and electron mobility μ of (20 ± 2) cm2/V s. Band gap energy (Eg) and absorption coefficient (α) are determined from the optical transmission and reflectance of the films. A direct transition with energy gap Eg = (1.60 ± 0.01) eV is obtained. Optical absorption coefficient in the range of photon energies hν > 2.0 eV is higher than 105 cm− 1. All these properties make PdS thin films a good alternative material for solar applications.