Interface Formation in Monolayer Graphene-Boron Nitride Heterostructures

Abstract

The ability to control the formation of interfaces between different materials has become one of the foundations of modern materials science. With the advent of two-dimensional (2D) crystals, low-dimensional equivalents of conventional interfaces can be envisioned: line boundaries separating different materials integrated in a single 2D sheet. Graphene and hexagonal boron nitride offer an attractive system from which to build such 2D heterostructures. They are isostructural, nearly lattice-matched, and isoelectronic, yet their different band structures promise interesting functional properties arising from their integration. Here, we use a combination of in situ microscopy techniques to study the growth and interface formation of monolayer graphene-boron nitride heterostructures on ruthenium. In a sequential chemical vapor deposition process, boron nitride grows preferentially at the edges of existing monolayer graphene domains, which can be exploited for synthesizing continuous 2D membranes of graphene embedded in boron nitride. High-temperature growth leads to intermixing near the interface, similar to interfacial alloying in conventional heterostructures. Using real-time microscopy, we identify processes that eliminate this intermixing and thus pave the way to graphene-boron nitride heterostructures with atomically sharp interfaces.

Order–disorder transition in a two-dimensional boron–carbon–nitride alloy

“…Recently, patterned regrowth 12,13 has been attempted for the spatially controlled synthesis of lateral junctions between electrically conductive graphene and insulating h-BN to make integrated circuitry 12 . The successful interfacing of these two isoelectronic materials to form hybrid monolayer film on Ru was also demonstrated by Sutter et al It is reported that the elimination of residual carbon adatoms is crucial to prevent unintentional intermixing of the G-BN interfaces 11 . In contrast to spatially segregated G-BN composite, intermixing of B, C and N atoms under thermodynamic non-equilibrium conditions may lead to semiconducting h-BC x N alloys 9,14,15 .…”

“…S2). In the work reported by Sutter et al 11 , shallow lines were imaged in the mixed BCN (boron-carbonnitride) regions. These lines appeared to be relatively disordered and their atomic structures and chemical composition were unknown.…”

“…The structural similarity between graphene (G) and h-BN motivates the alloying of the two to achieve ternary hexagonal boron-carbon-nitride (h-BC x N) composite with tunable electronic properties [5][6][7][8][9][10][11] . However, the ability to undergo homophilic (C-C) as well as heterophilic (C-B, C-N and BN) in h-BC x N generates a rich variety of polymorphic structures, making the precise control of their chemical stoichiometry and geometry formidable.…”

Direct chemical conversion of graphene to boron- and nitrogen- and carbon-containing atomic layers

“…Progress in this direction has been limited by difficulties in achieving scalable growth of uniform h-BN layers using chemical vapour deposition, a technique used to deposit high-quality graphene layers [11][12][13][14][15][16][17][18][19] . There have also been a few attempts to co-deposit graphene and h-BN domains to build hybridized two-dimensional boron carbonitride (h-BNC) atomic layers [10][11][12][13][14][15][16][17][18][19][20][21][22] . This coexistence of seamless graphene and h-BN domains inspires us to explore the synthesis of large area and high-quality h-BN atomic layers by substitutions of carbon atoms in graphene with boron and nitrogen.…”

Synthesis of High‐Quality Graphene and Hexagonal Boron Nitride Monolayer In‐Plane Heterostructure on Cu–Ni Alloy

“…Sequential growth of graphene/ h ‐BN on catalytic metal surfaces via chemical vapor deposition (CVD) has been extensively studied to form in‐plane heterostructure 9, 10, 14, 15, 16, 17, 18, 19, 20. Templated growth of h ‐BN starting from CVD graphene edges on copper has been realized with lattice coherency of the two crystals 14, 16.…”