Synthesis and characterization of antimony-doped n-type silicon quantum dots

Growth of Sb/SiN multilayers, followed by high-temperature annealing, was shown to be an effective strategy for synthesizing Sb-doped Si quantum dots (Si-QDs). The doping concentration of Sb (from 0.32 at.% to 1.82 at.%) was controlled by varying the thickness of Sb sublayer. Moderate Sb concentrations were found to enhance the formation of Si-H QDs. Photoluminescence (PL) results show that the nonradiative recombination defects caused by Sb impurities increased with the increase of Sb content, which leads to the decrease of the emission intensity. Hall measurements demonstrate that as the carrier concentration increases, the mobility of Hall decreases, and the conductivity increases at first and then decreases with the increase of Sb content. It is indicated that the excessive high Sb doping will deteriorate the conductive properties. The observed n-type electrical behavior and great enhancement increase in conductivity of the Sb-doped Si-QDs film suggest an effective Sb doping. A p-n junction was formed between Sb-doped Si-QDs and a p-type c-Si substrate, exhibiting good rectifying properties.