Improving InGaN heterojunction solar cells efficiency using a semibulk absorber

We demonstrate enhanced short circuit current density and power conversion efficiency in InGaN heterojunction solar cells using a semibulk absorber (multi-layered InGaN/GaN structure), with 8% indium concentration. The semibulk absorber shows peak external quantum efficiency of 85% and short current density of 0.57 mA/cm2 under AM 1.5 G, i.e. almost four times higher than the typical InGaN solar cells based on single thick InGaN absorber. The power conversion efficiency is around 0.39% under AM 1.5 G, almost three times higher than state of the art for 8% indium incorporation. The improvement in power conversion efficiency is attributed to the enhancement in structural quality of the InGaN absorber. Simulations and experimental results are presented for an in depth investigation of the parameters limiting the power conversion efficiency of the solar cell. The semibulk absorber is an elegant solution for the realization of highly efficient InGaN-based PIN heterojunction solar cells.