Bulk photovoltaic effect in two-dimensional ferroelectric semiconductor $\alpha$-In$_2$Se$_3$

TL;DR

This paper demonstrates that the 2D ferroelectric semiconductor $ ext{In}_2 ext{Se}_3$ exhibits a significant bulk photovoltaic effect with high current density under visible light, surpassing traditional ferroelectric materials and broadening photovoltaic application prospects.

Contribution

The study provides the first experimental evidence of bulk photovoltaic effect in $ ext{In}_2 ext{Se}_3$, a 2D ferroelectric semiconductor, showing enhanced response due to its narrow bandgap and out-of-plane polarization.

Findings

Photovoltaic current density nearly 100 times greater than conventional ferroelectrics.

Enhanced bulk photovoltaic response in the visible spectrum.

Potential for broad spectral photovoltaic applications.

Abstract

Bulk photovoltaic effect, which arises from crystal symmetry-driven charge carrier separation, is an intriguing physical phenomenon that has attracted extensive interest in photovoltaic application due to its junction-free photovoltaic and potential to surpass Shockley-Queisser limit. Whereas conventional ferroelectric materials mostly suffer from extremely low photocurrent density and weak photovoltaic response at visible light wavelengths. Emerging two-dimensional ferroelectric semiconductors with coupled visible light absorption and spontaneous polarization characteristics are a promising alternative for making functional photoferroelectrics. Herein, we report the experimental demonstration of the bulk photovoltaic effect behavior based on the 2D ferroelectric semiconductor {$\alpha$-InSe caused by an out-of-plane polarization induced depolarization field. The {$\alpha$-InSe device exhibits enhanced bulk photovoltaic response in the visible light spectrum owing to its narrow bandgap. It was demonstrated that the generated photovoltaic current density was nearly two orders of magnitude greater than conventional bulk ferroelectric materials. These findings highlight the potential of 2D ferroelectric semiconductor materials for bulk photovoltaic applications in a broad spectral region.