Flattening van der Waals heterostructure interfaces by local thermal treatment

Abstract

Fabrication of custom-built heterostructures based on stacked 2D materials provides an effective method to controllably tune electronic and optical properties. To that end, optimizing fabrication techniques for building these heterostructures is imperative. A common challenge in layer-by-layer assembly of 2D materials is the formation of bubbles at atomically thin interfaces. We propose a technique for addressing this issue by removing the bubbles formed at the heterostructure interface in a custom-defined area using the heat generated by a laser equipped with raster scanning capabilities. We demonstrate that the density of bubbles formed at graphene-ReS2 interfaces can be controllably reduced using this method. We discuss an understanding of the flattening mechanism by considering the interplay of interface thermal conductivities and adhesion energies between two atomically thin 2D materials.

Moiré patterns in graphene–rhenium disulfide vertical heterostructures

“…The typical height of the bubbles is 10-20nm and their typical width is 80nm. This aspect ratio is consistent with previous reports 13 and reflects the specific adhesion energy of the two layers. In Figure 2(b) we show the averaged scanning tunneling spectra over areas in Figure 2(a) both on the graphene/ReS2 heterostructure as well as on the bare ReS2.…”

Systematic THz study of the substrate effect in limiting the mobility of graphene

“…Among extrinsic limiting factors, scattering due to charged impurities is known to play a significant role 19 . Charged impurities can be present in the underlying substrate 20 , trapped between the film and substrate 21 , or on the surface of graphene in fabrication residues 22 .…”

Systematic THz Study of the Substrate Effect in Limiting the Mobility of Graphene

“…Among extrinsic limiting factors, scattering due to charged impurities is known to play a significant role 19 . Charged impurities can be present in the underlying substrate 20 , trapped between the film and substrate 21 , or on the surface of graphene in fabrication residues 22 .…”