Analytical study of electro-elastic fields in quantum nanostructure solar cells: the inter-nanostructure couplings and geometrical effects

摘要

Recent investigations on multifunctional piezoelectric semiconductors have shown their excellent potential as photovoltaic components in high-efficiency third-generation quantum nanostructure (QNS) solar cells. The current work is devoted to studying the electro-elastic behavior of high-density QNS photovoltaic semiconductors within which initial mismatch strains of arrays of quantum dots (QDs) or quantum wires (QWRs) induce coupled electro-mechanical fields. The inter-nanostructure couplings which are of great importance in high-density QNS arrays are incorporated in the presented analytical framework. In practice, QNSs with different geometries such as spherical, cuboidal, or pyramidal QDs and circular or rectangular QWRs can be grown. The present solutions take into consideration any arbitrary geometry of grown QNSs as well. In addition, the current methodology treats functional variations of electro-mechanical properties of anisotropic QNSs and their difference with electro-elastic constants of the anisotropic barrier. Furthermore, nonuniform initial misfit strains within high-density QDs have been incorporated and revealed that change the induced strains by as much as 52 percent in comparison with the case of uniform misfit strains in InAs/GaAs pyramidal QDs. When different material properties of QNSs and barrier have shown to make small effects on the induced fields, it has been observed that both inter-QD couplings and QD geometry significantly affect the coupled induced electro-elastic fields either within QNSs or in the piezoelectric barrier.