Efficiency improvement of graphene/AlGaAs/GaAs Schottky junction solar cells by minimizing optical losses through front and rear surface texturing

Abstract

Heterojunction Schottky solar cells based on gallium arsenide (GaAs) are prominent in photovoltaic research due to their remarkable properties. However, these solar cells face several challenges, such as surface reflection, reduced generation of electron–hole pairs, and insufficient light absorption persist. This work explores, for the first time, the structural, optical, and electrical properties of graphene (Gr)/AlGaAs/n-GaAs solar cells by optimizing front surface texturing, incorporating a back surface field (BSF) layer, and further enhancing performance through BSF layer texturing. The first feature of the proposed structure (Prop-Str) is a nano/micro-textured surface to enhance light management in Gr/AlGaAs/n-GaAs heterojunction Schottky solar cells. The results show that a textured surface with a period width of 1 μm and a depth of 600 nm achieves a short-circuit current density (JSC) of 23.51 mA/cm2, an open-circuit voltage (VOC) of 0.97 V, and a power conversion efficiency (PCE) of 19.99%. The n+-InAl0.65Ga0.35P BSF layer is added on the back surface as the second feature of the Prop-Str that increases the PCE by 3% due to a strong electric field in the n-GaAs/n+-InAlGaP heterojunction. The third characteristic of the Prop-Str enhances performance by texturing the BSF layer, improving internal reflection and light trapping. This modification significantly boosts light scattering and low-energy photon absorption, leading to higher JSC and VOC. Ultimately, the Prop-Str achieves a PCE of 25.37%. These findings underscore the effectiveness of front surface texturing and BSF layer optimization in achieving high-performance and cost-effective ultrathin GaAs solar cells.