Design of Planar Si Thermoelectric Generators with Phononic Crystal Patterning

This paper presents the design and optimization of planar poly-Si thermoelectric generators (TEGs) for energy harvesting application. Temperature and electric potential distributions arc simulated using material parameters, which were experimentally obtained from test structures, by the finite element method to evaluate the performance of TEGs. TEGs with unpatterned membranes or membranes with phononic crystal (PnC) nanostructures are investigated to evaluate the increase in power density by nanopatterning. The power density is increased by PnC nanopatterning with larger holes and the optimal bridge length decreases owing to a higher thermal resistance. The series of simulations shows that nanopatterning increases the power density 2.5 times at a smaller bridge length and is also advantageous from the viewpoint of mechanical strength.