Tempered Dewetting of Metal Films: A platform for networked 2D crystal membranes

The controlled dewetting and recrystallization of metal films with two-dimensional (2D) crystal over-layers enables the formation of highly textured metallic films, together with a network of metallic pores and suspended 2D crystal membranes. Mechanically-exfoliated and chemical-vapor deposited (CVD-grown) 2D crystals (e.g., graphene, h-BN, and transition-metal dichalcogenides (TMDs)) were transferred on top of metallic thin films on SiO₂/Si substrates to modify the dewetting and recrystallization dynamics. After heat treatment, metal films capped with 2D crystals become textured and form pores that can span up to 60% of the planar surface area, depending on annealing conditions and 2D crystal quality. The network of suspended membranes was found to have significantly different optical and electronic properties than the supported regions. For example, enhancement in photoluminescence of nearly three orders of magnitude and spatial surface potential variations up to 300 mV. The process capabilities are exemplified through a series of heterostructures of different metal/2D crystal materials where the resulting properties highlight the influence of the networked topography.