Investigation into the current loss in InAs/GaAs quantum dot solar cells with Si-doped quantum dots

Our previous studies have shown that introducing Si doping in quantum dots (QDs) can help QD solar cells achieve higher voltage. However, this improvement came at the cost of current loss. In this work, we continue to investigate the cause of the current loss and propose a method to recover it without compromising the voltage. Photoluminescence measurements have confirmed that optimizing the thickness of the GaAs layers in the i-region can lead to strong current gain (∼14%) with minimal voltage loss (<3%) and alteration of the QD quality. The capacitance–voltage measurement results support that the current gain mainly originates from the increased depletion width. (paper)