A novel observation of controlled carrier hopping process in B-doped Si nanocrystal/SiC multilayers at low temperatures

Recent advances in quantum computing devices make studies on the carrier transport behaviors of silicon nanocrystals (Si NCs) under cryogenic temperature a most important subject. In this work, we study the electrical properties modified by B dopants in Si NC/SiC multilayers. Mobility measurement shows that the scattering mechanism that dominates in our samples in a low temperature range is ionized impurity scattering. Three carrier transport behaviors are identified as variable range hopping (VRH) (20–100 K), multiple phonon hopping (MPH) (100–500 K) and thermally-activated mechanisms (500–660 K). At temperature ranges as low as 30 K, we observe the effect of the Coulomb gap in B-doped Si NC/SiC multilayers that obey the Efros and Shklovskii (ES) law, which was not present in our previous studies concerning Si NC multilayers. The crossover temperature T_C is observed to increase with rising B-doping concentrations, which demonstrates another interesting effect of doping in controlling the electrical properties of Si NCs.