Analysis of the High Conversion Efficienciesβ-FeSi2and BaSi2n-i-p Thin Film Solar Cells

Abstract

Bothβ-FeSi2and BaSi2are silicides and have large absorption coefficients; thus they are very promising Si-based new materials for solar cell applications. In this paper, the dcI-Vcharacteristics of n-Si/i-βFeSi2/p-Si and n-Si/i-BaSi2/p-Si thin film solar cells are investigated by solving the charge transport equations with optical generations. The diffusion current densities of free electron and hole are calculated first. Then the drift current density in the depletion regions is obtained. The total current density is the sum of diffusion and drift current densities. The conversion efficiencies are obtained from the calculatedI-Vcurves. The optimum conversion efficiency of n-Si/i-βFeSi2/p-Si thin film solar cell is 27.8% and that of n-Si/i-BaSi2/p-Si thin film solar cell is 30.4%, both are larger than that of Si n-i-p solar cell (ηis 20.6%). These results are consistent with their absorption spectrum. The calculated conversion efficiency of Si n-i-p solar cell is consistent with the reported researches. Therefore, these calculation results are valid in this work.