Related papers: Gate-controlled Guiding of Electrons in Graphene
In graphene, the extremely fast charge carriers can be controlled by electron-optical elements, such as waveguides, in which the transmissivity is tuned by the wavelength. In this work, charge carriers are guided in a suspended ballistic…
We have fabricated graphene devices with a top gate separated from the graphene layer by an air gap--a design which does not decrease the mobility of charge carriers under the gate. This gate is used to realise p-n-p structures where the…
We fabricated graphene pnp devices, by embedding pre-defined local gates in an oxidized surface layer of a silicon substrate. With neither dielectric-material deposition nor electron-beam irradiation on the graphene, we obtained…
Guiding electronic waves in a manner similar to photon transmission in optical fibers is key for developing the electron-optics toolbox. Here we outline a `weak guiding' approach, in which efficient diffraction around disorder results in…
We propose the theory of transport in a gate-tunable graphene p-n junction, in which the gradient of the carrier density is controlled by the gate voltage. Depending on this gradient and on the density of charged impurities, the junction…
The motion of massless Dirac-electrons in graphene mimics the propagation of photons. This makes it possible to control the charge-carriers with components based on geometrical-optics and has led to proposals for an all-graphene…
We have developed a device fabrication process to pattern graphene into nanostructures of arbitrary shape and control their electronic properties using local electrostatic gates. Electronic transport measurements have been used to…
We study photodetection in graphene near a local electrostatic gate, which enables active control of the potential landscape and carrier polarity. We find that a strong photoresponse only appears when and where a p-n junction is formed,…
Graphene is a 2-dimensional (2D) carbon allotrope with the atoms arranged in a honeycomb lattice. The low-energy electronic excitations in this 2D crystal are described by massless Dirac fermions that have a linear dispersion relation…
We present a beam splitter in a suspended, ballistic, multiterminal, bilayer graphene device. By using local bottomgates, a p-n interface tilted with respect to the current direction can be formed. We show that the p-n interface acts as a…
Unipolar transport is demonstrated in a bilayer graphene with a series of p-n junctions and is controlled by electrostatic biasing by a comb-shaped top gate. The OFF state is induced by multiple barriers in the p-n junctions, where the band…
Graphene's linear dispersion relation and the attendant implications for bipolar electronics applications have motivated a range of experimental efforts aimed at producing p-n junctions in graphene. Here we report electrical transport…
Graphene is an ultrathin material, which allows us to control surface phenomena by means of field-effect gating. Among various surface phenomena, photo-oxidation is known to be a facile method to largely control the electronic structure of…
A far-reaching goal of graphene research is exploiting the unique properties of carriers to realize extreme nonclassical electronic transport. Of particular interest is harnessing wavelike carriers to guide and direct them on submicron…
We perform electrical transport measurements in graphene with several sample geometries. In particular, we design ``invasive'' probes crossing the whole graphene sheet as well as ``external'' probes connected through graphene side arms. The…
The focusing of electric current by a single \textit{p-n} junction in graphene is predicted. We show that precise focusing can be achieved by fine-tuning the densities of carriers on the n- and p-sides of the junction to equal values,…
With the advent of high mobility encapsulated graphene devices, new electronic components ruled by Dirac fermions optics have been envisioned and realized. The main building blocks of electron-optics devices are gate-defined p-n junctions,…
We investigate the electron transport in smooth graphene pn junctions, generated by gradually varying electrostatic potentials. The numerically calculated coherent current flow patterns can be understood largely in terms of semi-classical…
We demonstrate a tunneling and rectification behavior in bilayer graphene. A stepped dielectric top gate creates a spatially modulated electric field, which opens the band gap in the graphene and produces an insulating region at the p-n…
Graphene with its dispersion relation resembling that of photons offers ample opportunities for applications in electron optics. The spacial variation of carrier density by external gates can be used to create electron waveguides, in…