硫化时间对化学浴沉积法制备Bi2S3薄膜性能的影响

Thin films of bismuth sulfide have gained more attention in the fabrication of photovoltaic cells owing to their promising properties, such as absorption coefficient, direct bandgap, earth-abundant components, and environmental compatibility. In this regard, we examined the effect of sulfurization time on Bi 2 S 3 films prepared via chemical bath deposition (CBD) at a constant sulfurization temperature of 350 ℃. The as-grown Bi 2 S 3 films were sulfurized for 30, 60, and 90 min. X-ray diffraction patterns showed that (130) was the predominant orientation with an orthorhombic crystal structure of space group Pbnm for all the layers sulfurized at various time periods. The films sulfurized for 60 min exhibited large crystallites with low dislocation density and minimal lattice strain. Raman spectroscopy confirmed the existence of A g and B 1g characteristic vibrational modes of Bi 2 S 3 . Atomic force microscopy images showed that surface roughness increased with increasing sulfurization time. Energy-dispersive analysis revealed that the Bi 2 S 3 films had a near-stoichiometric composition. The evaluated optical band gap values are found to be decreased from 1.70 to 1.37 eV with an increase of sulfurization time. In addition, the obtained bandgap values were closely aligned with those of the ideal absorber layers. Hall measurements demonstrated that all sulfurized Bi 2 S 3 thin films exhibited p-type conductivity. The Bi 2 S 3 films sulfurized for 60 min showed good quality layers with superior morphological, structural, optical, and electrical properties, making them ideal cost-effective absorber layers for fabricating thin-film solar cells.