2D MATERIALS BASED HETEROSTRUCTURES FOR QUANTUM TUNNELING: A LITHOGRAPHY FREE TECHNIQUE

Speaker: Ali Ibrahim M, Alzahrani

Abstract: A lithography free technique for the direct fabrication of two-dimensional (2D) material-based tunnel junctions has been developed. Graphene/h-BN/Graphene single barrier tunneling devices were fabricated by direct deposition of graphene, h-BN and graphene sequentially using a plasma enhanced chemical vapor deposition technique on Si/SiO₂ substrates. The I-V data were shown to follow the barrier dependent quantum tunneling behavior. The study was further expanded to realize resonant tunneling devices by (i) asymmetric doping of graphene and (ii) double barriers (DB) consisting of Graphene/h-BN/Graphene/h-BN/Graphene. DB Tunneling junctions with varying well widths were studied while different degrees of doping were used for the other devices. The I-V characteristics of tunneling current of both devices showed resonant tunneling behavior at room temperature with a negative differential conductance. The behavior could be explained with quantum mechanical tunneling models. Finally, Josephson tunneling was demonstrated for MgB₂/h-BN/MgB₂ junctions.