Size-effects on shift-current in layered CuInP$_2$S$_6$
Abstract
Two-dimensional ferroelectrics have recently emerged as a promising avenue for next-generation optoelectronic and photovoltaic devices. Due to the intrinsic absence of inversion symmetry, 2D ferroelectrics exhibit bulk photovoltaic effect (BPVE), which relies on hot, non-thermalized photo-excited carriers to generate a photo-induced current with enhanced performances thanks to efficient charge separation mechanisms. The absence of a required p-n junction architecture makes these materials particularly attractive for nanoscale energy harvesting. Recent studies have reported enhanced BPVE in nanometer-thick CuInPS ferroelectric embedded between two graphene wafers, driven by relatively strong polarization and reduced dimensionality. Short circuit photocurrent density values have been observed to reach up to mA/cm. In this paper, we demonstrate that the shift-current mechanism alone cannot fully account for these high conductivity values, suggesting that additional mechanisms may play a significant role. Furthermore, our work confirms the existence of a strong size effect, which drastically reduces the shift-conductivity response in the bulk limit, in agreement with experimental observations.
Cite
@article{arxiv.2512.05796,
title = {Size-effects on shift-current in layered CuInP$_2$S$_6$},
author = {Francesco Delodovici and Brahim Dkhil and Charles Paillard},
journal= {arXiv preprint arXiv:2512.05796},
year = {2025}
}