InGaN/GaN multiple quantum well solar cells with an enhanced open-circuit voltage

In this paper, InGaN/GaN multiple quantum well solar cells (MQWSCs) with an In content of 0.15 are fabricated and studied. The short-circuit density, fill factor and open-circuit voltage (V_oc) of the device are 0.7 mA/cm², 0.40 and 2.22 V, respectively. The results exhibit a significant enhancement of V_oc compared with those of InGaN-based hetero and homojunction cells. This enhancement indicates that the InGaN/GaN MQWSC offers an effective way for increasing V_oc of an In-rich In_xGa_1-xN solar cell. The device exhibits an external quantum efficiency (EQE) of 36% (7%) at 388 nm (430 nm). The photovoltaic performance of the device can be improved by optimizing the structure of the InGaN/GaN multiple quantum well.