ABSTRACT
In order to explore novel physical properties, phenomena, and also to realize potential applications of nanoparticles, the synthetic method is very important. Traditionally nanoparticles were synthesized only from chemical and physical methods, including sol-gel, solvothermal process and ion sputtering technique. Generally, two main approaches for nanoparticles synthesis are bottom-up and top-down approaches. It includes methods such as mechanical milling, laser ablation, and thermal decomposition. Nanoparticles are synthesized by decomposing metals at a particular temperature undergoing chemical reaction that produce secondary products. Sputtering is usually a deposition of a thin layer of nanoparticles followed by annealing. The thickness of the layer, temperature, and duration of annealing and substrate type determines size and shape of nanoparticles. The presence of undesired elements in nanoparticles may halve their efficiency and results in contamination and secondary reaction in process. The crystallography of nanoparticles is carried out by a powder X-ray, electron, or neutron diffraction to determine the structural arrangement.
