Recombination Analysis of Tunnel Oxide Passivated Contact Solar Cells

In this paper, an analytical model has been developed to observe the recombination losses involved in a tunnel oxide passivated contact solar cell with a carrier-selective layer constituting polycrystalline silicon (poly-Si). The main focus of this paper is to observe the contribution of each component of recombination current density and its effect on open-circuit voltage, Voc. The effect of emitter saturation current density (Joe), surface recombination velocity, substrate thickness, and doping density of carrierselective layer on Vochas been presented. The analysis indicates that Voc= 766 mV can be achieved for Joe = 2 fA/cm2, and a doping density of poly-Si > 1021cm-3in a c-Si/SiO2/poly-Si contact for a 50-μm-thick substrate in case of ideal surface passivation. For identical conditions, Voc attains a lower value of 750 mV for a 180-μm-thick substrate. The dependence of Voc on bandgap of tunnel layers has also been observed by considering other materials like Si3N4and SiC. These results from the analytical model have been compared with results from a simulation using automat FOR simulation of HETerostructures v2.5 and have been found to be in good agreement with each other.