Preparation of carbon nanoparticles by laser ablation in water for photodetector applications

Carbon Nanoparticles CNPs have been produced using pulsed laser ablation of a graphite target in DI water. Microstructural characterization and optical properties of the CNPs were carried out using X-ray Diffraction (XRD), Transmission electron microscopy (TEM), UV-VIS, and photoluminescence (PL) spectroscopy. TEM investigation showed that CNPs having a spherical shape with some aggregations in nanoparticles. The XRD results confirm the crystalline structure of carbon nanoparticles with a hexagonal phase along (100) plane. The absorption result of carbon nanoparticles exhibits a remarkable increase in its intensity with increasing laser energy. The Photoluminescence spectra showed that the intensity peak increase with increasing laser energy due to the increase in NPs concentration, with some blue shift in wavelength resulting from increases in the particle size of the prepared nanoparticles. For the optoelectronic devices, a CNPs/Si heterojunction photodetector is fabricated by drop-casting colloidal carbon nanoparticles on the silicon wafer. The laser energy impact on the electrical characteristics and photosensitivity of the heterojunction has been thoroughly investigated.