Design and mechanism of cost-effective and highly efficient ultrathin (< 0.5 μm) GaAs solar cells employing nano/micro-hemisphere surface texturing

Low aspect-ratio nano/micro-hemisphere surface texturing is introduced for improving light management in ultrathin GaAs solar cells. A 200 nm thick film textured by the optimal GaAs nano/micro-hemisphere array with both the hemisphere diameter and array periodicity of 500 nm can achieve >90% light absorption from 1.44 to 2.5 eV, lying in the high photon density energy regime of the solar spectrum for GaAs. The excellent light confinement and low aspect ratio, which is thus convenient for conformal deposition of electrodes for efficient photogenerated carrier collection of the proposed structure will facilitate realization of highly efficient and cost-effective ultrathin GaAs solar cells.