Comparison of electron and hole mobilities in multiple quantum well solar cells using a time-of-flight technique

A difficulty of carrier transport in multiple quantum well (MQW) solar cells is one critical issue that limits their cell performance. Here, direct measurement of electron and hole transport times across InGaAs/GaAsP MQWs has been carried out using our proposed time-of-flight measurement technique on p-on-n and n-on-p MQW structures, respectively. The corresponding effective mobilities are determined, allowing us to approximate the MQW region as a quasi-bulk material with smaller carrier mobilities than a bulk crystal. The result shows similar effective electron and hole mobilities. This results in the similar tendency of cell performance in p-on-n and n-on-p MQW solar cells.