Abstract
In-plane heterostructure of monolayer hexagonal boron nitride (h-BN) and graphene is of great interest for its tunable bandgap and other unique properties. Here, we reveal a H2-induced etching process to introduce triangular hole in triangular-shaped chemical vapor deposited individual h-BN crystal. In this study, we synthesized regular triangular-shaped h-BN crystals with the sizes around 2-10 μm on Cu foil by chemical vapor deposition (CVD). The etching behavior of individual h-BN crystal was investigated by annealing at different temperature in an H2:Ar atmosphere. Annealing at 900 °C, etching of h-BN was observed from crystal edges with no visible etching at the center of individual crystals. While, annealing at a temperature ≥950 °C, highly anisotropic etching was observed, where the etched areas were equilateral triangle-shaped with same orientation as that of original h-BN crystal. The etching process and well-defined triangular hole formation can be significant platform to fabricate planar heterostructure with graphene or other two-dimensional (2D) materials.
Highlights
Exfoliation has been used to extract monolayer of h-BN and other 2D materials to investigate the fundamental properties and device applications[20,21,22]
In contrast to previous findings, we demonstrate for first time possibility of opening triangular hole in individual triangular-shaped h-BN crystals, which will enable to grow graphene and other 2D materials in the etched hole to fabricate a well-defined heterostructure
In case of graphene synthesized on Cu foil, hexagonal etched holes by H2 have been observed with etching towards zigzag direction[40]
Summary
Exfoliation has been used to extract monolayer of h-BN and other 2D materials to investigate the fundamental properties and device applications[20,21,22]. In case of graphene synthesized on Cu foil, hexagonal etched holes by H2 have been observed with etching towards zigzag direction[40]. Increasing the annealing temperature to 900 °C, etching of h-BN was observed from crystal edges with no visible etching in center of individual crystal as shown in fig.
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