**5. Current application**

The BN material shows excellent chemical, thermal, and mechanical properties, which are utilized in different applications. The industrial application of 2D BN is yet to be realized due to the lack of large-area thin film synthesis techniques. To date, large-area films with uniform thickness are hard to fabricate. The h-BN is known for its wide direct bandgap (~5.9 eV), small lattice mismatch with graphene (1.7%), and high thermal conductivity. The BN nanosheets have been employed in several semiconductors device applications, such as transparent membranes, encapsulation materials, tunneling barriers, and high dielectric materials [81]. For instance, some graphene devices fabricated on the h-BN show very high mobility in order of 60,000 cm2V-1 s-1, which is far greater than III-V devices that exploit 2DEG (two-dimensional electron gas) properties [82].

Interestingly, an ultrathin layer of BN is sandwiched between the graphene layer (C-BN-C), making a field effect tunneling transistor heterostructure. The study revealed that the h-BN nanosheet forms a good tunnel barrier [83]. Ranjan et al. studied dielectric breakdown failure of thin h-BN films. The study found that the breakdown field is 21 MV cm−1 for 3-nm-thick h-BN. The breakdown field suggests that h-BN is more suitable for gate dielectric than high-quality silicon dioxide [84].
