Optimization of the thermoelectric power factors in 50-nm n- and p-type silicon nanowires by varying the doping concentration

Abstract

The electric and the thermoelectric properties of 50-nm n- and p-type silicon nanowires (SiNWs) obtained by doping with boron di-fluoride and phosphorus, respectively, were investigated by varying the doping concentration from 1.0 x 10(20) to 2.5 x 10(21) cm (-3). The SiNWs were manufactured using conventional semiconductor processing techniques. The values of the optimized maximum power factor values were 1.59 and 2.43 mW center dot m K--1(-2) for the n- and the p-type SiNWs at a doping concentration of 4.0 x 10(20) cm(-3). For doping concentrations higher than over 4.0 x 10(20) cm(-3), the electrical resistivity was larger and the Seebeck coefficient was sharply lower due to imperfections in the crystal structure. For lower doping concentrations below 4.0 x 10(20) cm(-3), the increased resistivity had a dominant impact on the power factor.