Improved growth conditions of pulsed laser-deposited Pbl_2 nanostructure film: towards high- photosensitivity Pbl_2/CNTs/Si photodetectors

摘要

Nanostructured PbI_2 films were grown by laser deposition technique at a substrate temperature of 45 ℃ was demonstrated. Herein, we attempted to improve and control the crystal growth of PbI_2 film and p-PbI_2/MWCNTs/p-Si photodetector by finding the optimum laser fluence. X-ray diffraction XRD results illustrate that the grown PbI_2 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/cm~2 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/cm~2 was stoichiometric PbI_2. The Photosensitivity investigations reveal that responsivity as high as 0.4 A/W at 610 nm was obtained for the p-PbI_2/MWCNTs/p-Si photodetector prepared at 3.9 J/cm~2 without post-deposition annealing.