Thermoelectric Energy Conversion: How Good Can Silicon Be?
  Lack of materials which are thermoelectrically efficient and economically attractive is a challenge in thermoelectricity. Silicon could be a good thermoelectric material offering CMOS compatibility, harmlessness and cost reduction but it features a too high thermal conductivity. High harvested power density of 7W/cm2 at deltaT=30K is modeled based on a thin-film lateral architecture of thermo-converter that takes advantage of confinement effects to reduce the thermal conductivity. The simulation leads to the conclusion that 10nm thick Silicon has 10 times higher efficiency than bulk. 
M. Haras, V. Lacatena, F. Morini, J.-F. Robillard, S. Monfray, T.   Skotnicki and E. Dubois
cond-mat.mtrl-sci cond-mat.mes-hall physics.comp-ph