Apparatus and methods for controlled growth and assembly of nanostructures

An apparatus comprising:

• a closed container;
• a first substrate including at least one reaction site disposed within said closed container;
• heating apparatus for heating said first substrate;
• at least one aperture in said closed container capable of use for introducing a reaction species to said first substrate, wherein a nanostructure is grown from said reaction site upon introduction of the reaction species to said reaction site;
• and
• wherein the growth process of the nanostructure is controlled by a controller that continuously monitors the properties of the nanostructure and the at least one reaction site, and by controlling process variables based on the monitored properties of the nanostructure and the at least one reaction site.