摘要
In this work, for the first time, the addition of aluminum oxide nanostructures (Al O NSs) grown by glancing angle deposition (GLAD) is investigated on an ultrathin Cu(In,Ga)Se device (400 nm) fabricated using a sequential process, i.e., post-selenization of the metallic precursor layer. The most striking observation to emerge from this study is the alleviation of phase separation after adding the Al O NSs with improved Se diffusion into the non-uniformed metallic precursor due to the surface roughness resulting from the Al O NSs. In addition, the raised Na concentration at the rear surface can be attributed to the increased diffusion of Na ion facilitated by Al O NSs. The coverage and thickness of the Al O NSs significantly affects the cell performance because of an increase in shunt resistance associated with the formation of Na Se and phase separation. The passivation effect attributed to the Al O NSs is well studied using the bias-EQE measurement and J–V characteristics under dark and illuminated conditions. With the optimization of the Al O NSs, the remarkable enhancement in the cell performance occurs, exhibiting a power conversion efficiency increase from 2.83% to 5.33%, demonstrating a promising method for improving ultrathin Cu(In,Ga)Se devices, and providing significant opportunities for further applications.