Controlled doping of silicon nanocrystals investigated by solution-processed field effect transistors

The doping of semiconductor nanocrystals (NCs), which is vital for the optimization of NC-based devices, remains a significant challenge. While gas-phase plasma approaches have been successful in incorporating dopant atoms into NCs, little is known about their electronic activation. Here, we investigate the electronic properties of doped silicon NC thin films cast from solution by field effect transistor analysis. We find that, analogous to bulk silicon, boron and phosphorus electronically dope Si NC thin films; however, the dopant activation efficiency is only ∼10^-2-10^-4. We also show that surface doping of Si NCs is an effective way to alter the carrier concentrations in Si NC films.