Mechanical regulation strategy for heterogeneous piezoelectric semiconductor thermoelectric structure based on energy conversion

The piezoelectric properties inherent in piezoelectric semiconductors facilitate the manipulation of charge carrier redistribution, enabling the fabrication of electronic devices with adjustable characteristics. However, despite this capability, our understanding of the energy conversion and transfer mechanisms within such devices remains limited. By discarding the assumption of low injection and the approximation of depletion layer, a nonlinear model was developed on piezoelectric semiconductor thermoelectric structure (PS-TES), considering the penetration of hot electrons and regulation of mechanical loadings. The presented model reveals that the input electric energy is partitioned, with a portion being converted into electric potential energy stored (EPES) in non-equilibrium carriers and another portion being the energy dissipation (ED) due to the electrothermal action. Furthermore, from an energy conservation standpoint, a interesting competitive phenomenon between electric potential energy conversion and energy dissipation is obtained. The power of external electric energy input and internal electric energy conversion can be manipulated via mechanical loadings, thereby adjusting the energy conversion process of PS-TES. Finally, we found that the compressive loadings can increase EPES and reduce ED, thereby optimizing the cooling effect at cold end. While tensile loadings can reduce EPES and increase ED, thus causing the PS-TES to locally heat up and produce a heating effect. This study potentially offers a means to switch the performance of TES and provides fresh insights into energy conversion processes within piezoelectric semiconductors.