Free-standing graphene shows unique and outstanding mechanical and electronic properties, however when it is in close proximity to the substrate surface its physical properties change due to the lattice mismatch inducing electronic and transport parasitic effects thus limiting its immediate applications for the device technology. To address this problem, we have investigated 2D heterostructures based on fabricated graphene (G) layers and boron nitride nanosheets (BNNS), a material of similar lattice parameter and an identical crystal structure to that of graphene. This concept has already shown a number of electronic applications in the area of 2D materials and flexible electronic devices. We contributed by analyzing nanoscale features in fabricated bilayer graphene and BNNS samples that were prepared individually on copper foils, transferred between substrates by polymethyl methacrylate (PPMA) technique and used to fabricate heterostructures. Prior fabricating the tunneling devices, crystal lattices and layered structures of as-synthesized graphene and BNNS materials were analyzed. Nanoscale morphology down to a single atomic layer was identified using high resolution transmission electron microscope. The stacking BNNS sheets showed B3-N3 hexagonal lattice suitable for developing G/BNNS heterostructure 2D device architecture. We have fabricated the prototype devices based on G/BNNS/Metal, G/SiO2, and G/BNNS/SiO2 heterostructures to study the physical properties of each involved layer and their effect on performance of the charge tunneling through the device. In the case of G/BNNS/Metal, the I(V) measurements have shown typical Schottky diode characteristics with very low forward voltage drop indicating out-of-plane tunneling with low sheet resistance of graphene layer what makes it suitable for developing practical hetero-2D tunneling devices. A theoretical model based on current tunneling is proposed to explain fabricated 2D device behavior.
5:00 PM–7:00 PM Apr 24, 2019 (US - Arizona)
PCC North, 300 Level, Exhibit Hall C-E