US Patent 7763530 - Nanoparticle doping with ionic salts

http://www.freepatentsonline.com/7763530.html

Thermal diffusion and ion implantation are common techniques used to dope semiconductor materials and produce solid state electronic devices. However, bulk doping techniques are less efficiently applied to nanoparticle semiconductors. This patent from the University of Cape Town teaches a method using ionic salts which may prove more efficient in doping of nanoparticles. Claim 1 reads:

1. A method of doping semiconductor particles to change the carrier concentration and/or type of the semi-conductor material, the method comprising

mixing a quantity of semiconductor particles, having a particle size in the range 1 nm to 100 μm, with an ionic salt or a preparation of ionic salts, so that each semiconductor particle as a whole is doped by adsorption or absorption of one or more ionic species of the ionic salt preparation of ionic salts.