Synthesis of Nanomaterials and Nanostructures

This chapter discusses about the synthesis of nanomaterials and nanostructures. These are prepared by two main approaches: Bottom-up and top-down approach. Bottom up approach describes the synthesis of nanomaterials from small scale to larger scale. Carbon nanotubes synthesis by chemical vapor deposition technique and nanoparticle synthesis using liquid phase synthesis, colloidal method, sol-gel method, hydrothermal synthesis and polyol method comes under bottom-up approach. Conventional carbon nanotube synthesis methods like arc discharge and laser ablation require high temperature for their production. Chemical vapor deposition has been a promising method for carbon nanotube growth in term of their quality and production, Growth mechanism for carbon nanotubes is still an ongoing research based on their growth and pre-treatment conditions. Unlike, top-down approach involves breaking up from larger scale to smaller scale. Lithography is typical example of top-down approach. Photolithography involves the transferring of pattern from mask to the substrate. The typical range of patterning is 100 nm for photolithography while electron-beam lithography can fabricate strcutures even below 10 nm.