Effect of doping on the dynamic nuclear polarization of porous silicon nanoparticles

Abstract

Porous Si nanoparticles (NPs) with different doping degree were prepared using low-load metal assisted catalytic etching and subjected to dynamic nuclear polarization at 3.4 T and 6.7 T. Thermal oxidation of Si was applied to form paramagnetic centers of dangling bond type in Si/SiO2 interface, which were used to polarize 29Si nuclei. The doping significantly affected the gained polarization and buildup times: high doping degree generally led to lower and faster polarization compared to the low doping. On the other hand, slight p-type or n-type doping was necessary to achieve the highest polarization of about 11 %.