Thermoelectric power generation using large-area Si/SiGe pn-junctions with varying Ge content

Abstract

We present strategies for improving the power output of large-area pn-junctions for thermoelectric power conversion. The gradient of the pn-junction's built-in potential is used to separate thermally generated electron–hole pairs. An externally applied temperature gradient along the pn-junction induces a driving force to both electrons and holes which results in currents from the hot end to the contacts. Due to the exponential dependence of the thermal generation rate on the local temperature, the temperature distribution within the device strongly influences the device behaviour. We present simulation results describing the possible application of graded SiGe alloys in order to control the temperature distribution and thus improve the power output and efficiency of thermoelectric generators using large-area pn-junctions.