Recovering the Semiconductor Properties of the Epitaxial Group V 2D Materials Antimonene and Arsenene

Antimonene (2D-Sb) is attracting considerable attention because of its environmental stability and exceptional electronic and optical properties. Recently, 2D-Sb was grown on germanium (Ge) substrates, thus laying the groundwork for the integration of 2D-Sb-based devices in standard semiconductor processing. However, the relatively strong Ge-Sb interactions were found to suppress the semiconducting properties expected for monolayer 2D-Sb. To overcome this limitation, this work demonstrates that Ge passivation prior to epitaxy allows tuning the electronic properties of 2D-Sb. Ab initio calculations indicate that hydrogen and methyl passivation yields semiconducting epitaxial 2D-Sb, whereas halogen passivation yields degenerate semiconductors. A similar behavior is observed for 2D-As and 2D-AsSb on silicon. Finally, using molecular beam epitaxy combined with in situ low-energy electron microscopy, we demonstrate that the growth of 2D-Sb can be achieved on passivated Ge. These results will stimulate the development of growth processes to facilitate the integration of these emerging 2D materials in scalable devices.