Improved growth conditions of pulsed laser-deposited PbI₂ nanostructure film: towards high- photosensitivity PbI₂/CNTs/Si photodetectors

Nanostructured PbI₂ films were grown by laser deposition technique at a substrate temperature of 45 °C was demonstrated. Herein, we attempted to improve and control the crystal growth of PbI₂ film and p-PbI₂/MWCNTs/p-Si photodetector by finding the optimum laser fluence. X-ray diffraction XRD results illustrate that the grown PbI₂ films are polycrystalline with hexagonal structure along (001) and the film crystallinity degraded with increasing the laser fluence. Scanning electron microscope SEM revealed that the particle size decreases as laser fluence increase and film deposited at 3.9 J/cm² was dense and the grains distributed uniformly over the surface of the film. Energy dispersive X-ray EDX data confirms that the film stoichiometry depends on laser fluence and the film deposited at 3.9 J/cm² was stoichiometric PbI₂. The Photosensitivity investigations reveal that responsivity as high as 0.4 A/W at 610 nm was obtained for the p-PbI₂/MWCNTs/p-Si photodetector prepared at 3.9 J/cm² without post-deposition annealing.