Effect of the Number Shots of Laser on Structural Transformations and Optical Properties of ZnS Nanoparticles Thin Films

Effects of the number of shots of laser and annealing temperature on the structural, morphological, and optical properties of zinc sulfide nanoparticles (ZnS NPs) thin films, prepared by pulsed laser deposition technique (PLD), were investigated. XRD results show that ZnS NPs exhibit a hexagonal phase at 623 k. Transformation in the shape of nanoparticles to nano flowers and nano rods appeared with increasing number of shots of laser at the same annealing temperature (623 K) was observed from scanning electron microscopy (SEM) images. The optical properties were studied from all transmittance data. The experimental results show that the as-deposited ZnS NPs film exhibit a cubic structure and the crystallinity increased in the annealed films. It is also found that the grain size of the as grown samples at 300 K, rises linearly from 9 to 11 m with increasing the number of shots from 1000 to 3000 and rapidly from 10 to 18 nm after annealing at 623 K. Additionally, the increase of the number of shots from 1000 to 3000 leads to a decrease in the energy gap values and increases their values after heat treatment keeping their behavior decreasing as the number of shots of laser increases. Also, photoluminescence (PL) measurements explained quenching its value after annealing temperature