Low‐Energy GeP Monolayers with Natural Type‐II Homojunctions for SunLight‐Driven Water Splitting

Abstract

The discovery of two new GeP monolayers (GeP‐2 and GeP‐4) with structural similarity to the experimentally synthesized C2/m (GeP‐3) phase, that their structures can be decomposed to hypothetical (2,2), (4,4), and (3,3) GeP nanotubes, respectively, is reported. The calculated total energies show that both GeP‐2 and GeP‐4 possess comparable stabilities to the experimentally realized GeP‐3, and they are confirmed to be dynamically stable according to their phonon vibrational spectrum. The current study also shows that three homojunctions (GeP‐2 and GeP‐4, GeP‐2 and GeP‐3, and GeP‐3 and GeP‐4) with perfect boundary can be naturally formed in GeP‐2, GeP‐3, and GeP‐4. The HSE06‐based electronic properties show that GeP‐2, GeP‐3, GeP‐4, and their homojunctions possess suitable band alignment and type‐II features for sunlight‐driven water‐splitting at both pH = 0 and pH = 7. These low‐energy GeP monolayers are desirable targets and highly expected to be synthesized in future experiments in view of their structural compatibility to GeP‐3 and the potential applications in water‐splitting.