Effect of Surface Passivation on Dopant Distribution in Si Quantum Dots: The Case of B and P Doping

Despite many efforts, the doping behavior in Si quantum dots (QDs) is still not well understood. Theoretical work shows that boron as an acceptor prefers to stay near the surface and phosphorous as a donor may stay close to the center in a perfectly hydrogen passivated QD. However, experiment studies seem suggesting an opposite trend. Using first-principle methods, we show that the discrepancy could be explained by the imperfectness of surface passivation of the QD. We find that, in QDs with hydrogen deficient or oxygen rich surfaces, phosphorous prefers the surface sites and boron may stay inside, consistent with experiment observations.