Design guidelines for a highly efficient high-purity germanium (HPGe)-based double-heterojunction solar cell

In spite of having higher carrier mobilities and absorption coefficients of germanium (Ge) than those of silicon (Si), there has been less focus on Ge-based solar cells due to the low bandgap and high-cost of Ge wafer as well as requirement of its high-purity level. Currently, availability of high-purity Ge (HPGe), the low-cost wafer slicing method and proper design guidelines make it possible to design HPGe-based solar cells. Accordingly, in this article, we have designed and simulated a novel n-CdS/p-HPGe/p+-BaSi2 based npp+ double-heterojunction solar cell, where HPGe, cadmium sulfide (CdS) and orthorhombic barium disilicide (beta-BaSi2) have been used as the absorber, window and back-surface field (BSF) layers, respectively. Using the solar cell capacitance simulator (SCAPS-1D), the effects of different physical…