Design Optimization of Large Area Si/SiGe Thermoelectric Generators

We present a comparison of large area pn-junction thermoelectric generators and classical thermoelectric modules. In contrast to conventional thermocouples, the thermal generation of carriers is explicitly used within the new device structures. The gradient of the pn-junction´s built-in potential causes the separation of the thermally generated carriers. For the application of waste heat recovery, the device is exposed to an external temperature gradient along the pn-junction which induces driving forces to both electrons and holes from the heated to the cooled end of the structure, where contacts are applied. The influence of device geometry and material composition on the device behavior is investigated. Simulation results obtained by our device and circuit simulator MiNiMOS-NT working in conjunction with the optimization framework SIESTA are presented