How shall we put multiple quantum wells in p-i-n structure for efficiency enhancement?

For the purpose of getting maximum short-circuit current for a InGaAs/GsAsP strain-compensated multiple-quantum-well (MQW) solar cell with a minimum drop in both open-circuit voltage and fill factor, we have optimized the position of the quantum wells in the i-region of a pin host structure. Numerical and experimental analysis revealed the best position, where the MQWs divide the i-region at a ratio of 1:3 for p-side and n-side, respectively. The physics behind this finding is that (1) MQWs should not touch the edge of either p- or n-region in order to avoid accumulation of majority carrier that deteriorates carrier transport at a short-circuit condition, and (2) MQWs should not be around the center of the i-region to avoid carrier recombination at a larger forward bias condition.