Efficiency improvement of Si quantum dot solar cells by activation with boron implantation

The activation of Si quantum dots (QDs) in general Si QD heterojunction solar cells fabricated by the co-deposition of Si and B is typically not effective, as a high concentration of B is required for effective activation. In order to address this issue, B atoms were injected by ion implantation after the formation of Si QDs in a SiO2 matrix. A Si QD solar cell was successfully realized when a Si QD layer was activated by the implantation of B ions followed by an annealing step. As a result, the power conversion efficiency of a Si QD solar cell realized by the ion implantation of B increased from 13.17% to 13.92%. The open-circuit voltage also increased from 523.03 mV to 529.64 mV in the Si QD solar cell created with the ion implantation of B.