EFFECT OF LASER FLUENCE ON THE CHARACTERISTICS OF CdSe NANOPARTICLES PREPARED BY LASER ABLATION IN METHANOL

摘要

The effect of laser fluence on structural, morphological, optical, and electrical properties of CdSe nanoparticles NPs prepared by irradiating a CdSe target, immersed in methanol, with Nd:YAG laser pulses at laser fluences in the range of (1.32-2.92) J/cm~2 has been studied. X-ray diffraction XRD measurements disclosed that the CdSe NPs were of wurtzite hexagonal crystal structure. Transmission electron microscopy investigation revealed that the synthesized CdSe particles are spherical and have an average particle size in the range of (37-94 nm). Scanning electron microscope SEM and transmission electron microscope ТЕМ investigations showed that the shape and size of the synthesized CdSe NPs depend on laser fluence. The nanoparticles distribution was correlated with laser fluence. Atomic force Microscopic AFM investigations showed highly dispersed ball-shape CdSe particles. The optical energy gap of CdSe nanoparticles prepared has been determined from optical properties and found to be in the range of (1.7-2.05 eV). Optical constants of CdSe NPs were determined from transmittance and reflectance spectra. Hall measurement showed that the CdSe nanoparticles were n-type and their carrier concentration and mobility was investigated.