How are quantum dots made?
One process for creating quantum dots is to create a quantum well. A quantum well is created by scattering a semiconductor with impurities, a very precise process known as doping, this then causes very intersting effects to take place within the semiconductor. If for instance silicon doped with electron donor atoms such as phosphorus it becomes an N, or negative-type, semiconductor, which contains one excess electron for every atom of dopant. These excess electrons have nowhere to bind, so they flow easily through the material, just as the more numerous excess electrons do inside a conductive metal. Doping with electron borrowers like aluminum produces a P, or positive material, which conducts “holes,” or spaces where an electron isn’t (http://www.wired.com/wired/archive/9.10/atoms.html) When a P is place next to a N it forms a P-N junction which acts as a electrical gate valve of sorts, only letting elctrons flow in one direction. When a P is placed on top and on bottom of a N, a sort
