Efficient Use of Low-Bandgap GaAs/GaSb to Convert More than 50% of Solar Radiation into Electrical Energy: A Numerical Approach

Abstract

A recent trend in photovoltaic technology is to aim to enhance the conversion efficiency of this energy harvesting technique. Although multijunction solar cells offer high efficiency, factors such as fabrication cost, cost per watt of energy produced, etc. limit their application. An alternative approach based on a lower-bandgap GaAs/GaSb dual-junction solar cell is proposed herein. For efficient use of longer wavelengths of the solar spectrum, a model for a simple antireflection coating (ARC)-less GaAs/GaSb dual-junction cell with a double back-surface field layer was optimized. The model was simulated using the Silvaco ATLAS technology computer-aided design (TCAD) tool and validated based on parameters such as the quantum efficiency, photogeneration rate, and spectral response. The model predicts conversion efficiency of 54%, better than some reported experimental results.