Giant modulation of the photogalvanic effect in two-dimensional SnP2S6/CuInP2S6 ferroelectric heterojunctions

The photogalvanic effect (PGE) enables the direct conversion of light into current in non-centrosymmetric materials, providing a promising route toward self-powered optoelectronics devices. However, achieving large and tunable photocurrents in two-dimensional system remains a significant challenge. Here, we demonstrate a giant and hierarchically tunable PGE in a SnP2S6/CuInP2S6 ferroelectric heterojunction through the combined control of device contact symmetry, ferroelectric polarization, and optical polarization. Asymmetric contacts break the spatial inversion symmetry and enhance the photocurrent ∼50× compared with symmetric contacts at 0.8 eV. In addition, switching the ferroelectric polarization of CuInP2S6 leads to an eightfold increase in photocurrent at 2.4 eV. Moreover, circularly polarized light generates a photocurrent that is 13 times larger than that induced by linearly polarized light at the same photon energy. These results demonstrate an effective strategy for achieving giant photocurrent modulation in two-dimensional ferroelectric heterojunctions and provide foundations for high-performance and reconfigurable optoelectronic devices.