Time-tuned growth of nanostructured CdS thin films via CBD for enhanced photodetector performance
摘要
In this work, cadmium sulfide (CdS) nanostructured thin films were deposited by a low-cost chemical bath deposition (CBD) process with growth durations between 1 and 4 h. The influence of deposition time on structural, morphological, optical, electrical, and photoresponse properties was systematically analyzed. X-ray diffraction confirmed cubic CdS with enhanced crystallinity, as the crystallite size increased from 10.4 to 32.4 nm. SEM revealed a transition from fibrous features to nanoflake morphologies with extended deposition. Optical studies showed a redshift of the absorption edge and narrowing of the band gap from 2.34 to 2.26 eV. Electrical analysis indicated a significant decrease in resistivity and a concurrent rise in carrier mobility and concentration. Photodetectors fabricated with 4 h films exhibited superior performance, achieving a responsivity of 3.72 A/W, detectivity of 1.85 × 1010 Jones, and external quantum efficiency of 86.8%. These findings demonstrate that prolonged CBD growth enhances film quality and optoelectronic performance, establishing CdS nanostructured films as strong candidates for high-efficiency photodetectors and photovoltaic applications.