Straightforward strategy for selecting and tuning substrates for two-dimensional material epitaxy

Abstract

Wafer-scale two-dimensional (2D) materials grown directly on substrates via epitaxy methods are desired for building high-performance electronic devices. Up to now, the selection of the appropriate substrates has been dominated by trial and error, which has greatly hindered the mass production of 2D materials for device applications. In this paper, based on the evolutionary trend of the formation energy during growth, we propose that the epitaxy of monoelemental 2D materials on metal substrates can be classified into three types, and only the third type with a significant energy benefit has the opportunity to grow into large-scale 2D monolayers. By extensive first-principles calculations, we find that this concept can coincide well with experimental reports when the energy threshold is set to 0.6 eV/atom, which provides a straightforward way to evaluate interlayer interactions between substrates and adsorbates. Furthermore, taking the growth of blue phosphorene (blue-P) on Ag(111) as an example, a heterogeneous epitaxial strategy to achieve a transition in growth type by surface alloying is proposed. We verify the feasibility of this strategy and investigate the nucleation process of blue-P on the ${\mathrm{Ag}}_{2}\mathrm{Sb}$ surface alloy. Our findings provide a valid path for substrate selection and tuning, and we believe that this general strategy will stimulate the development of the large-scale synthesis of 2D materials.