Space charge layer effects in silicon studied by in situ surface transport.

Electronic properties of low dimensional structures on surfaces can be comprehensively explored by surface transport experiments. However, the surface sensitivity of this technique to atomic structures comes along with the control of bulk related electron paths and internal interfaces. Here we analyzed the role of Schottky-barriers and space charge layers for Si-surfaces.

Surface-dominated transport on a bulk topological insulator.

Topological insulators are guaranteed to support metallic surface states on an insulating bulk, and one should thus expect that the electronic transport in these materials is dominated by the surfaces states. Alas, due to the high remaining bulk conductivity, it is challenging to achieve surface-dominated transport. Here we use nanoscale four-point setups with a variable contact distance on an atomically clean surface of bulk-insulating Bi2Te2Se.

Exceptional ballistic transport in epitaxial graphene nanoribbons.

Graphene nanoribbons will be essential components in future graphene nanoelectronics. However, in typical nanoribbons produced from lithographically patterned exfoliated graphene, the charge carriers travel only about ten nanometres between scattering events, resulting in minimum sheet resistances of about one kilohm per square. Here we show that 40-nanometre-wide graphene nanoribbons epitaxially grown on silicon carbide are single-channel room-temperature ballistic conductors on a length scale greater than ten micrometres, which is similar to the performance of metallic carbon nanotubes.

Edge-states in graphene nanoribbons: a combined spectroscopy and transport study.

Graphene structures of finite size are expected to reveal exceptional electronic and magnetic properties which are highly attractive for future nano-technological applications. In this study we have looked at the edge-states in graphene nanoribbons (GNR) grown by self-assembly on mesa structured SiC(0001) templates. By means of a 4-tip STM/SEM system, both local spectroscopy and lateral transport have been performed in situ on the same nanostructures.