Barrier Thickness Dependence of Photovoltaic Characteristics of InGaN/GaN Multiple Quantum Well Solar Cells

摘要

We discuss the influence of the barrier thickness of an InGaN/GaN multiple quantum well (MQW) structure on solar cell performance. As barrier thickness decreases, short-circuit current density increases and open-circuit voltage decreases. The open-circuit voltage is much lower than expected from the absorption edge because of the large leakage current and large ideality factor of diodes owning to the carrier tunneling through the barrier. An MQW with a 3-nm-thick barrier layer shows a much longer carrier lifetime than that with a 9-nm-thick barrier layer. This is one possible reason for a higher short-circuit current in solar cell with the 3-nm-thick barrier MQW structure than that with the 9-nm-thick barrier MQW.