Stoichiometry and Morphology Analysis of Thermally Deposited V2O5-x Thin Films for Si/V2O5-x Heterojunction Solar Cell Applications

In recent decades, dopant-free Si-based solar cells with a transition metal oxide layer have gained noticeable research interest as promising candidates for next-generation solar cells with both low manufacturing cost and high power conversion efficiency. Here, we report the effect of the substrate temperature for the deposition of vanadium oxide (V2O5-x, 0 <= X <= 5) thin films (TFs) for enhanced Si surface passivation. The effectiveness of SiOx formation at the Si/V2O5-x interface for Si surface passivation was investigated by comparing the results of minority carrier lifetime measurements, X-ray photoelectron spectroscopy, and atomic force microscopy. We successfully demonstrated that the deposition temperature of V2O5-x has a decisive effect on the surface passivation performance. The results confirmed that the aspect ratio of the V2O5-x islands that are initially deposited is a crucial factor to facilitate the transport of oxygen atoms originating from the V2O5-x being deposited to the Si surface. In addition, the stoichiometry of V2O5-x TFs can be notably altered by substrate temperature during deposition. As a result, experimentation with the fabricated Si/V2O5-x heterojunction solar cells confirmed that the power conversion efficiency is the highest at a V2O5-x deposition temperature of 75 degrees C.

Automated summary

This study reports on an improved method for enhancing surface passivation of silicon by adjusting the substrate temperature during the deposition of V2O5-x. The results show that the deposition temperature of V2O5-x has a decisive effect on the surface passivation performance, and the aspect ratio of V2O5-x islands plays a crucial role in facilitating the transport of oxygen atoms.