Edge-Epitaxial Growth of Graphene on Cu with a Hydrogen-Free Approach

Abstract

We demonstrate a new concept of edge-epitaxial growth that enables the van der Waals (vdWs) epitaxial graphene growth on different Cu facets. This approach simply entails turning off hydrogen during the nucleation stage of the atmospheric pressure chemical vapor deposition process. Fundamentally, different from conventional vdWs growth, this new type of epitaxial growth benefits from the strong binding between the graphene edge and a metal step in a hydrogen-absent atmosphere. This interaction fixes the orientation of graphene grains in energetically preferable configurations at the early nucleation stage. Specifically, single-crystal graphene grains grown on Cu(111) have irregular shapes with rough edges and are misaligned slightly with respect to the Cu(111) lattice. Graphene grains form with two possible orientations that are rotated by ∼30° on the Cu(100) surface, and grains with three preferred orientations are observed on Cu(110). Density functional theory calculations further prove the enhanced edge-metal step interaction and thus validate the experimental observations of these specific graphene crystal orientations on Cu(100) and Cu(110). Observation of this new type of edge-epitaxial growth helps to clarify many contradictory graphene growth phenomena that have been observed previously and may provide insights that will facilitate an understanding of the growth of other materials using the chemical vapor deposition method.

Direct Growth of Graphene Nanowalls on Silicon Using Plasma-Enhanced Atomic Layer Deposition for High-Performance Si-Based Infrared Photodetectors

“…Graphene is a promising material for optoelectronic applications due to its wide absorption spectrum and high carrier mobility, which make it promising for high-speed photodetection and communication. − Although Si has been widely used for optoelectronic applications, it lacks absorption of infrared (IR) light with wavelength above 1200 nm. A combination of graphene and Si has drawn much attention in developing of new devices by making use of their unique properties of both the materials. − It is well known that the chemical vapor deposition (CVD) growth of graphene on metallic substrates is the most effective method, but with high-temperature above 1000 °C, to obtain high quality graphene. − However, the transferring of graphene grown on metal substrates onto a desired substrate for device fabrication inevitably causes damage and metal residues into the transferred graphene, which limits the performance of the fabricated device. − To avoid this problem, the direct growth of graphene on the Si substrate is of great significance. − However, the direct thermal CVD growth of graphene on Si substrates is very difficult as the formation of silicon carbide takes place even at 900 °C . Hence, a low-temperature plasma-enhanced CVD (PECVD) is normally used to grow graphene materials on Si substrates directly, by which graphene nanowalls (GNWs) were mainly formed on the Si surface.…”

Hydrogen-Mediated CVD Epitaxy of Graphene on SiC: Implications for Microelectronic Applications

“…4 This procedure suffers from important electron−phonon scattering at the interface between Gr and the substrate underneath, resulting in carrier mobility reduction. 10 Alternative substrates were then efficiently explored for the catalytic growth of Gr such as metals (Ni,11 Pt, 12 Ru, 13 Pd, 14 Cu 15 ), III−V alloys, 16 and boron nitride (h-BN), 17 proving that high-quality Gr can be properly transferred on various substrates. However, even if the exfoliation technique is simple, inexpensive, and perfectly fitted to fundamental physics, its technological development is not enough when it comes to applications (in particular, for the microelectronic industry).…”

Characteristics, properties, synthesis and advanced applications of 2D graphdiyne versus graphene

“…Over the past decades, numerous efforts have been made to break the symmetric bonds and induce localized magnetic moments in GR either theoretically or experimentally using the vacancy approach, the edge approach, the sp 3 approach, and so on. 101–103…”