Potential of multiple-quantum well tandem solar cells based on GaPxAs1-x/GayIn1-yAs

Recent development in band-gap engineering technology has lead researches in the field of tandem photovoltaic solar cells to examine the feasibility of low-dimensional multi-junction solar cell. This is achieved by the combination of only two materials with different band-gaps, piled vertically with different thicknesses. It is theoretically possible to tailor a set of effective band-gaps responding to the requirement of tandem solar cells with a maximum efficiency. In the present work we investigate the potential of tandem solar cells based on GaPAs/GaInAs multiple quantum well structure. Efficiency limit has been previously calculated using the detailed balance principle for multi-junction solar cells. Adjusting the number of wells and their widths and barrier depth gives the possibility of varying the effective band-gap. Numerical resolution of Schrodinger equation for GaPAs/GaInAs multiple quantum well demonstrates the potential of this III-V compound to achieve a wide range of effective band-gaps varying from 2.27 to 0.70 eV. However, this material could be used to manufacture low-dimensional tandem solar cells and can achieve tandem solar cells up to six sub-cells, that can yield an efficiency limit up to 59% for series constrained AM 1.5 global radiation.