The successful isolation of graphene flakes from graphite has prompted researchers to seek other two-dimensional materials that can be obtained by exfoliation from stacked bulk solids. Recent examples include hexagonal boron nitride (h-BN), MoS2 and WS2. Pulickel Ajayan, Angel Rubio, Yansheng Yin and colleagues have now shown that it is possible to prepare a stacked film made of alternating nanosheets of h-BN and graphene.
The researchers — who are based at institutes in the US, Spain, China and India — first obtain graphene and h-BN flakes separately by ordinary exfoliation, and then simply combine the two materials under sonication to obtain free-standing hybrid films. Spectroscopic investigations show that the hexagonal arrangement of both the carbon atoms, and the boron and nitrogen atoms is generally maintained. Interplane covalent bonds are also possible, due to the presence of some dangling bonds, and may contribute to the stability of the film.
Theoretical calculations hint at original optoelectronic properties stemming from the interaction at the interface between materials with dissimilar electronic properties. For example, h-BN (an insulator) could absorb ultraviolet light and directly inject charges into the graphene (a conductor) layer.
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Mix and match. Nature Nanotech (2012). https://doi.org/10.1038/nnano.2012.139