Significant Pressure-Enhanced Photoelectric Properties and Extended Spectral Response Range in Zn-Based Chalcopyrite ZnGeP2

As a commercial chalcopyrite, the ternary Zn-based semiconductor ZnGeP2 is a promising material because of its economical and practical applications in photocatalytic, nonlinear optic, and photoelectric applications. Nevertheless, there is still an urgent need to explore an effective approach to further optimize the photoelectric-related properties of ZnGeP2. Herein, the superior photoelectric properties of ZnGeP2 with high photocurrent density (Jph) of 1467 μA/cm2, and photoresponsivity (R) of 780.3 mA/W were obtained at 21.4 GPa, which enhanced 3 orders of magnitude higher compared with initial values. Intriguingly, the photoresponse range of ZnGeP2 was extended to 1650 nm. Extensive high-pressure spectral analysis and theoretical simulation revealed that the metal phase (Fm3̅m) started at 14.3 GPa, followed by a successive metallization process dominated by a mixed-phase state up to 23.3 GPa, which contributed to the significant pressure-enhanced photoelectric properties of ZnGeP2. These findings demonstrate significant improvement of the photoelectric properties in ZnGeP2 via external pressure, which also provides methods to modify the photoelectric properties of other chalcopyrites.