title: Coherent quantum transport features in carbon superlattice structures.
abstract: Whilst resonant transmission is well understood and can be fully harnessed for crystalline superlattices, a complete picture has not yet emerged for disordered superlattices. It has proven difficult to tune resonant transmission in disordered diamond-like carbon (DLC) superlattices as conventional models are not equipped to incorporate significant structural disorder. In this work, we present concurrent experimental and theoretical analysis which addresses resonant transmission in DLC superlattices. Devices were fabricated by growing alternate layers of DLC with different percentages of sp3hybridized carbon.Coherent quantum transport effects were demonstrated in these structurally disordered DLC superlattices through distinct current modulation with negative differential resistance (NDR) in the current-voltage (I-V) measurements. A model was developed using tight-binding calculations assuming a random variation of the hopping integral to simulate structural (bond-length) disorder. Calculations of the I-V characteristics compliment the interpretation of the measurements and illustrate that while DLC superlattice structures are unlike their classical counterparts, the near-field structural order will help with the confinement of quantised states. The present model provides an empirical guide for tailoring the properties of future devices, giving rise to much hope that carbon electronics operating at high frequencies over large areas can now be developed.
authors.affiliation: Nano-scale Transport Physics Laboratory, School of Physics, and Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa.
authors.forename: R
authors.initials: R
authors.lastname: McIntosh
authors.affiliation: Advanced Technology Institute, University of Surrey, Guildford, Surrey, GU2 7XH, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Henley
authors.affiliation: Advanced Technology Institute, University of Surrey, Guildford, Surrey, GU2 7XH, UK.
authors.forename: S R P
authors.initials: SRP
authors.lastname: Silva
authors.affiliation: Nano-scale Transport Physics Laboratory, School of Physics, and Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa.
authors.forename: S
authors.initials: S
authors.lastname: Bhattacharyya