Thermoelectric properties of 50-nm-wide n- and p- type silicon nanowires

Abstract

For the evaluation of thermoelectric properties in silicon nanowires (SiNWs), thermoelectric test structures are manufactured, including 50-nm-wide n- and p-type SiNWs, micro-heater and temperature sensors using a conventional lithography method on 8 in. silicon wafer. For the optimization of thermoelectric properties in SiNWs, we have evaluated Seebeck coefficients and power factors of n- and p-type SiNWs by varying the nanowire length 10, 40 μm and temperature (from 310 to 450 K). The results show that the maximum Seebeck coefficients and power factors are $146.37 \,{\upmu} \hbox {V/K}, 1.15\,\times \,10^{3}\, \hbox {W}\,\hbox {m}^{-1}\,\hbox {K}^{-2}, 113.83\; {\upmu} \hbox {V/K}, 0.67\,\times \,10^{3}\, \hbox {W}\,\hbox {m}^{-1}\,\hbox {K}^{-2}$ and $-113.25\; {\upmu} \hbox {V/K}, 0.59\,\times \,10^{3}\,\hbox {W}\,\hbox {m}^{-1}\,\hbox {K}^{-2}$ for $10, 40\; {\upmu} \hbox {m}$ long p-type and $40\; {\upmu}\hbox {m}$ long n-type SiNWs, respectively. The contribution of phonon-drag effect to thermoelectric power is discussed in the highly doped SiNWs.