Question: how are the nano atoms things formed?!?

Sabina Hatch answered on 13 Mar 2014:

It depends on what nano-structure you are looking make, but I use the bottom-up method. Where nano structures are formed using single atoms, as opposed to the top-down method which takes a large lump of material and removes small parts to form a nanostructure.

There are a lot of different techniques! The nanorods I grew during my PhD used a chemical procedure that encouraged atoms for grow from small “seed” particle. The atoms need something to grow from, this is the nucleation stage. From then on as you keep suppling atoms it then depends on the different surface energy of your crystal faces. The crystal faces with higher surface energy will grow the quickest. So in order to grow nanowires – you need a material that has a crystal structure that prefers growing along a particular direction for. e.g. c-axis (which is the perpendicular to the surface) rather than equally in all directions.

One of the most important part is the seed particle from which the nanostructure will grow, otherwise the atoms will form a thin film instead. Also if you can position the seed particle it will let you control where your nanowires grow.