Interface engineering of graphene-silicon Schottky junction solar cells with an Al₂O₃ interfacial layer grown by atomic layer deposition

The recent progress in graphene (Gr)/silicon (Si) Schottky barrier solar cells (SBSC) has shown the potential to produce low cost and high efficiency solar cells. Among the different approaches to improve the performance of Gr/Si SBSC is engineering the interface with an interfacial layer to reduce the high recombination at the graphene (Gr)/silicon (Si) interface and facilitate the transport of photo-generated carriers. Herein, we demonstrate improved performance of Gr/Si SBSC by engineering the interface with an aluminum oxide (Al₂O₃) layer grown by atomic layer deposition (ALD). With the introduction of an Al₂O₃ interfacial layer, the Schottky barrier height is increased from 0.843 V to 0.912 V which contributed to an increase in the open circuit voltage from 0.45 V to 0.48 V. The power conversion efficiency improved from 7.2% to 8.7% with the Al₂O₃ interfacial layer. The stability of the Gr/Al₂O₃/Si devices was further investigated and the results have shown a stable performance after four weeks of operation. The findings of this work underpin the potential of using an Al₂O₃ interfacial layer to enhance the performance and stability of Gr/Si SBSC.