Microstructural and electrical properties evaluation of lead doped tin sulfide thin films

Abstract

A low cost and simple spray methodology with nebulizer was employed to fabricate lead doped tin sulfide (SnS:Pb) thin films. Different doping weight percentages (1, 3, 5, 7, and 9 wt%) were used to prepare SnS:Pb thin films on glass substrates with 350 °C substrate temperature, and we subsequently investigated Pb element influence on microstructural, electrical, and optical properties. Structural studies using X-ray diffraction confirmed orthorhombic crystal structure with (111) plane preferred orientation and atomic force micrographs identified significant variation due to the different Pb wt%. Photoluminescence showed a strong band edge emission peak at 761 nm, with optical band gaps at 1.90–1.60 eV over the Pb dopant concentrations. Hall effect showed low electrical resistivity (3.01 × 10−2 Ω cm), high carrier concentration (~1.01 × 1019 cm−3), and high Hall mobility (~20.5 cm2 V−1 s−1) for 7 wt%, which is suitable to fabricate solar cell devices. The p–n junction properties were analyzed under dark and illumination conditions by current–voltage characteristics using the FTO/n-CdS/p-SnS:Pb/Al structure.