Influence of Sb-doping on structural, optical and UV photodetector properties of CdS thin films

The demand for high-performance photodetectors has driven extensive research into materials with superior optoelectronic properties. This study presents the fabrication and ultraviolet (UV) photodetection capabilities of antimony (Sb)-doped cadmium sulfide (CdS) thin films. The thin films were deposited via the nebulizer spray pyrolysis (NSP) method onto glass substrates. X-ray diffraction (XRD) analysis confirms the presence of a hexagonal crystal structure in all films, with the 2 wt% Sb-doped CdS film exhibiting the highest crystallinity. Morphological examination using FESEM revealed that Sb-doping led to the formation of larger, densely packed grains for 2 wt% doped film, enhancing its charge transport properties. Optical studies showed enhanced light absorption with Sb incorporation, making the material more effective for UV detection. The photodetector performance was assessed through current vs. voltage (I-V) measurements. The photodetector performance was evaluated under 365 nm UV illumination with an intensity of 1 to 5 mW cm⁻² at an applied bias of ± 5 V. Among the prepared thin films, the 2 wt% Sb-doped CdS film demonstrated remarkable photoresponse, achieving a responsivity (R) of 1.84 A W^-1, detectivity (D*) of 4.60 × 10⁹ Jones and an external quantum efficiency (EQE) of 626%. The device exhibited rapid response and recovery times of 1.02 s and 0.56 s, respectively. Furthermore, the photodetector maintained stable performance over extended cycles, highlighting its reliability for long-term UV sensing applications. These results highlight the potential of Sb-doped CdS thin films as efficient and durable materials for advanced UV photodetectors.