InGaP Solar Cell with InGaP Multiple Quantum Wells Grown under Optimized V/III Ratio

Indium gallium phosphide (InGaP) solar cells are widely used as top subcells in multi‐junction solar cells, however, there are large open‐circuit voltage (VOC) losses in InGaP solar cells. Improving the radiative efficiency by inserting an InGaP multiple quantum well (MQW) into the InGaP solar cell structure is a promising approach to enhancing the VOC of InGaP solar cells, but such InGaP MQW solar cells are not demonstrated. Moreover, the critical parameters, such as the V/III ratio for an InGaP MQW, are not investigated. This study investigates the optimal V/III ratio for enhancing the radiative efficiency of an InGaP MQW. Doublehetero structures are fabricated, comprising a 330 nm core layer with 55 periods of an InGaP MQW grown under varying V/III ratios. The InGaP MQW grown under V/III = 62 gives the highest photoluminescence intensity among all InGaP structures. An InGaP MQW solar cell grown at V/III = 62 exhibits a 2 mV VOC loss suppression compared with an InGaP bulk solar cell. Therefore, an InGaP MQW grown under proper growth conditions contributes to enhance the energy conversion efficiency of InGaP solar cells. This study provides relevant insights into InGaP MQW crystal growth and the performance improvement in InGaP solar cells. This study investigates the influence of the V/III ratio on the radiative efficiency (ηrad) of indium gallium phosphide (InGaP) multiple quantum well (MQW) structures. The ηrad increases with increasing V/III ratio. However, the ηrad degrades at excessively high V/III ratios. It is found that inserting an InGaP MQW grown under an appropriate V/III ratio improves the InGaP solar cell performance.