Mathematical Modelling of a Novel Hetero-junction Dual SIS ZnO-Si-SnO Solar Cell

For the last few decades scientists across the world have achieved significant improvement in performance of conventional silicon p-n junction solar cell. Sophisticated high temperature doping technology is unavoidable in the fabrication of these conventional solar cells. Back in 1970s scientists proposed an alternative solar cell technology with Schottky barrier which can cut down the burden on thermal budget of manufacturing process. Later the metal-semiconductor Schottky barrier further modified with hetero junction semiconductor-semiconductor solar cells. A thin intrinsic layer sandwiched between semiconductor-semiconductor junctions can repair the junction defect efficiently. These SIS solar cells became popular for its low thermal budget and considerable efficiency. In this paper we have tried to propose a mathematical model of a novel dual side SIS solar cell which is basically a multi junction solar cell. We have introduced a third semiconductor layer (SnO) at the back side of the cell which can provide an inversion layer much similar to PERT solar cell. This structure is first of its kind and thus a theoretical analysis is required before implementation. We have studied the effect of this back field on the performance of the cell and propose a mathematical model based on reciprocity theorem of charge collection. The efficiency of conventional ZnO-pSi SIS solar cell was computed ~5.2% while the back SnO p+ layer is expected to enhance the efficiency up to ~7.9% according to our mathematical model. We have concluded with significant mathematical justification to implement this structure with proposed electro-chemical experiments.