Two-Dimensional Metals Over, Inside, or Beneath Templates.

Two-dimensional (2D) metals have drawn great attention because of their extraordinary properties, especially in applications that favor van der Waals interaction. The development of advanced characterization tools has facilitated the understanding of formation or growth mechanisms of 2D metals. In this perspective, we discuss 5 common approaches to obtaining 2D metals, including, (top down) van der Waals squeezing and selective extraction, and (bottom up) electron beam-induced growth, self-assembly, and graphene-templated wet chemistry growth. The future opportunities are proposed in the summary section. Furthermore, challenges and problems such as thermodynamic stability and scalability in 2D material growth are proposed for the community to tackle.