Effects of carrier escape and capture processes on quantum well solar cells: a theoretical investigation

A theoretical model is proposed to study the effects of carrier escape and capture processes on the photocurrent of quantum well solar cells (QWSCs). The results show that solar cells with very deep quantum wells (QWs) will suffer from extremely slow escape processes and their photocurrent can be inferior to their bulk counterparts. The results suggest that only when the escape time is at least two-order of magnitude smaller than the carrier lifetime of QWs, solar cells will benefit from QW structures. The optimal band gap energies of QW materials for achieving the maximum photocurrent are also calculated and discussed.