Structural and optical properties of spray-pyrolysed Bi2S3 thin films

Thin layers of bismuth trisulfide (Bi2S3) have been prepared for the first time by the spray pyrolysis method on glass substrates from bismuth chloride (BiCl3) and thiourea (CS(NH2)2) solutions with a concentration of 0.2 M. Films deposited on substrate at 570 K have a polycrystalline structure with crystallites size in the order of 120 A. X-Ray characterization by grazing angles diffraction (GAD) at 0.4 and 2° shows crystalline structures in surface and volume. Diffraction spectra of these films are indexed in the orthorhombic system. Studies of optical absorption in the energy range 1.5–4 eV indicate an optical gap of 1.66 eV. The Hall effect measurements indicate a carrier concentration of n=3.45×1017 cm−3.