This project aims to develop a novel and cost effective process for creating advanced thermoelectric (TE) materials constructed from Si Nanowires (Si-nw) arrays, and to demonstrate, with a prototype device, its performance and ability to scale to mass-production for heat-to-electricity conversion. Implementing Si-nw will create a cost effective waste heat recovery system capable of achieving a heat-to-electricity conversion efficiency of at least 10% (~2.5 times more than market TE).