Automated and parallel transfer of arrays of oriented graphene ribbons

Abstract

The transfer of two-dimensional materials from their growth substrate onto application wafers is a critical bottleneck in scaling-up devices based on such nanomaterials. Here, we present an innovative approach to achieve the automated and simultaneous transfer of arrays of graphene ribbons, with precise control over their orientation and alignment onto patterned wafers. The transfer is performed in a simple, yet efficient apparatus consisting of an array of glass columns, strategically shaped to control ribbon orientation and arranged to match the destination wafer, coupled to a dual inflow/outflow pumping system. This apparatus enables the transfer of a custom array of parallel graphene ribbons in a fraction of the time required with traditional methods. The quality of the transferred graphene was evaluated using optical imaging, scanning electron microscopy, hyperspectral Raman imaging, and electrical transport: all consistently indicating that the transferred graphene exhibits excellent quality, comparable to a manual transfer by an expert user. The proposed apparatus offers several competitive advantages, including ease of use, high transfer throughput, and reduced nanomaterial consumption. Moreover, it can be used repeatedly on the same wafer to assemble arrays of overlayed materials with controlled relative orientations. This approach thus opens promising opportunities for the large-scale fabrication of various heterostructures and devices based on vertical assemblies of 2D nanomaterials.