Effect of magnetic field on the structural, optical, and electrical properties of CdS nanoparticles in distilled water by using pulsed laser ablation

Abstract

In this study, we investigated the impact that the incorporation of a magnetic field has on the properties of cadmium sulfide CdS nanoparticles as well as the performance of an n-CdS/p-Si heterojunction photodetector that was developed by the use of the pulsed laser ablation in a liquid method. Nd:YAG laser pulses (1.064 μm, 550 mJ) were utilized to ablate cadmium sulfide CdS nanoparticles in water. The synthesized nanoparticles were shown to have a polycrystalline hexagonal structure, as evidenced by the findings of the X-ray diffraction experiment, the crystallite size for cadmium sulfide CdS decreased from 4.611 nm to 4.518 nm. The lattice constants of cadmium sulfide CdS nanostructures were determined to be a = 4.1302, c = 6.702, and c/a=1.622. The strain and dislocation density of cadmium sulfide CdS exhibited an increase. Images taken from a field emission scanning electron microscope demonstrated the formation of spherical nanoparticles on the surface. A magnetic field was applied, increasing the CdS film's crystallinity. As a consequence of this enhancement, the particle size of the CdS decreased from 25.18 nm to 12.17 nm. A comparison was made between this and the size of the crystallites that appeared when no magnetic field was present. The EDS spectrum of magnetically prepared cadmium sulfide CdS films indicates the presence of Cd and S, and the weight percentage ratios [Cd]/[S], increase from 3.72 to 3.80. The transmission electron microscopy (TEM) pictures of CdS samples that were generated using a magnetic field contained particles of small size with a mean of 10.10 nanometers. From the FT-IR spectra of cadmium sulfide CdS prepared using a magnetic field within 400–4000 cm−1, the peaks (bands) of cadmium sulfide CdS at 617 cm⁻¹ represent the bending vibration of Cd-S.  As a result of the influence of a magnetic field, the optical energy gap of CdS nanoparticles increased from 2.30 eV to 2.72 eV, as indicated by the UV-Vis study. From PL emission spectra the values of the energy band gap of cadmium sulfide CdS increased from 2.45 eV at 505.7 to 2.47 eV when a magnetic field was applied. CdS NP films produced under the influence of a magnetic field were identified as having n-type characteristics by Hall effect assessments, Particle mobility was influenced by particle size. The effect of applying a magnetic field on the efficiency of the n-CdS/p-Si photodetector was investigated and analyzed. When a magnetic field was applied during ablation, the responsivity of n-CdS/p-Si heterojunction photodetectors increased from 0.498 A/W to 0.830 A/W at 510 nm. This was the result of the application of the magnetic field.