Several efforts have been made to create hybrid
nanomaterials to explore their novel properties compared to their individual constituents.[1][2] Studies have shown that nanohybrid materials distinctively utilize the best aspects of the individual constituents along with their novel functionalities though
structural integrity and
interfacial chemical bonding of the constituents.[3]
Atomic Structure
Graphene boron nitride nanohybrid materials are created through synthetic methods such as
electron beam welding[4] and
chemical vapor deposition.[5] Various different
heterostructures of graphene and boron nitride can be assembled. Due to their isostructural, nearly
lattice matched and isoelectronic properties, they can form a two-dimensional interface with a line boundary separating the structures.[6][7][8] Other unique structures include boron nitride coated
carbon nanotubes,[9] and double layers of graphene joined in a pillared fashion by a boron nitride nanotube. The junction created by this stacking arrangement can result in two different junction configurations: one symmetric junction with two heptagonal rings and one asymmetric junction with three octagonal rings.[10] Comparing the two configurations, the octagonal junction seems to be more stable due to higher pi-pi
stacking interactions which induces
orbital overlap and mixing between the C atoms of the graphene. This introduces a
higher band gap, which indicates more effective insulating properties.
Figure 1. Example of the heptagonal junction in pillars of Graphene and Boron-Nitride. This junction geometry induces more strain on the pillar, lowering stability of the structure, and does not significantly raise the band gap to an insulating level.[10]Figure 2. The octagonal junction when creating Graphene Boron-Nitride hybrids. This configuration is structurally more stable than the heptagonal, and creates orbital overlap in the pillar, spreading out the electron density and increasing the band gap of the material to resemble an electrical insulator.[10]
Properties
The properties of these hybrid materials range between the properties of the constituent atoms and between individual hybrid structures. Graphene is considered a zero band
semi-conductor and boron nitride is considered a wide gap semi conductor. Combining the two in various arrangements leads to a variable band gap which can be tuned by structure specifics to have various properties.[11] Multi-walled carbon nanotubes when coated with boron nitride exhibit enhanced thermal activity compared to the substituents, but act as an electrical insulator.[9] Graphene layers combined by boron nitride nanotubes exhibit similar band gap changes, but the strain of the ring position in the junction also induces a pseudomagnetic force on the ring structure due to the electron delocalization.[10]
Figure 3. Example of a single layer of alternating graphene and boron nitride nano ribbons. By controlling the thickness and geometry of each layer, the electronic and thermal properties can be tuned while still maintaining nearly identical mechanical properties as a single sheet of either boron nitride or graphene.[11]
Applications
Graphene boron nitride nanohybrid materials may be useful for further development in
nanoelectronics[12] and 3D thermal and mechanical properties.[13] Theoretical and experimental studies have demonstrated straining of graphene can result in high flexibility and can tune the electronic structure of graphene to produce enormous pseudomagnetic fields.[14] This new theory opens up new possibilities in straining graphene boron nitride hybrid to advance new concepts of electronics.
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abÖzçelik, V. O.; Durgun, E.; Ciraci, S. (2015). "Modulation of Electronic Properties in Laterally and Commensurately Repeating Graphene and Boron Nitride Composite Nanostructures". J. Phys. Chem. C. 119 (23): 13248–13256.
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^Sakhavand, N.; Shahsavari, R. (2015). "Dimensional Crossover of Thermal Transport in Hybrid Boron Nitride Nanostructures". ACS Applied Materials & Interfaces. 7 (33): 18312–18319.
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^Levy, N.; Burke, S. A.; Meaker, K. L.; Panlasigui, M.; Zettl, A.; Guinea, F.; Neto, A. H. C.; Crommie, M. F. (2010). "Strain-Induced Pseudo-Magnetic Fields Greater Than 300 Tesla in Graphene Nanobubbles". Science. 329 (5991): 544–547.
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