Extremely low thermal conductivity of high density and ordered 10 nm-diameter silicon nanowires array

We present the fabrication and thermal conductivity of a high-density and ordered 10nm-diameter Si nanowires (SiNWs) array for thermoelectric devices, realized through the use of a bio-template mask as well as neutral beam etching techniques. The SiNWs were embedded into spin-on-glass (SoG) to measure the thermal conductivity of the SiNWs-SoG composites. By decreasing the thickness of SiNWs-SoG composites from 100 nm to 30nm, the thermal conductivity was drastically decreased from 1.8 +/- 0.3 W m(-1) K-1 to 0.5 +/- 0.1 W m(-1) K-1. Moreover, when the electrical conductivities of 100 nm-long SiNWs were 1.7 x 10 S m(-1), 6.5 x 10(3) S m(-1) and 1.3 x 10(5) S m(-1), their thermal conductivities of SiNWs-SoG composites were 1.8 +/- 0.3 W m(-1) K-1, 1.6 +/- 0.2 W m(-1) K-1 and 0.7 +/- 0.2 W m(-1) K-1, respectively. The cross-plane thermal conductivity of the fabricated 10 nm diameter SiNWs-SoG composites was dependent on their thickness and the electrical conductivity of SiNWs, which were significantly decreased from bulk. Published by AIP Publishing.