Impact of Nd doping in Bi2S3 thin films coated by nebulizer spray pyrolysis technique for photodetector applications

In this study, cost effective & scalable nebulizer spray pyrolysis approach was used to produce varying concentrations of Bi2S3:Nd (0, 1, 3, 5 wt%) thin films on glass substrates and the effect of Nd dopants on the crystalline, morphological, optical and photo sensing properties of the Bi2S3 thin films were studied. From the XRD results, the diffraction pattern of the prepared Bi2S3:Nd thin films exhibits an orthorhombic structure for all concentrations of Nd dopants with a predominant peak along (130) plane. Upon increasing the concentration of Nd dopants up to 3 wt% the predominant peak intensity increases with an increase in crystallite size of 25 nm and decreases with a further increase in the incorporation of Nd dopant. The surface morphological studies showed uniform nanocrystalline morphology for all the Bi2S3 thin films. The UV-Vis absorption studies revealed higher absorption of the prepared thin films over UV region and narrowing of the energy gap from 2.18 to1.63 eV with the incorporation of Nd dopant from 0 to 3%, repectievely. The photo sensing properties of the fabricated devices showed higher responsivity (R), detectivity (D*), EQE, and rapid rise/fall time of 1.36 x 10-1 A/W, 3.05 x 1010 Jones, 43%, and 0.1/0.2 s for Bi2S3:Nd 3 wt% thin film photodetector confirming the suitability of the device for commercial photodetector applications.