We explore the effect of geometrical fluctuations on the electronic transport in rough Si nanowire (NW) thermoelectric devices of diameter D < 10 nm. At this scale, the quantum nature of transport is accounted in the computation of energy dependent transmission coefficients through a recursive green function algorithm. The rough 3D NW geometry is used as a direct input to simulations through the roughness height Δ and autocovariance length L. Using a non parabolic band structure, the channel conductance above 0.1 eV is drastically reduced in such NW with high D/Δ ratio. In addition, the roughness induced resistivity is only increased by 6% on the first energy level of 10 nm Si channels with Δ = 7.7 Å, showing possible application for high thermoelectric figures of merit ZT.
ASJC Scopus subject areas
- Physics and Astronomy(all)