Browsing by Author "Quandt, Alexander"

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Citation Count: Quandt, Alexander...et al. "About nanometer sized analogues of basic electronic and optical components", 2008 2nd Icton Mediterranean Wiınter (Icton-Mw)
About nanometer sized analogues of basic electronic and optical components
(IEEE, 2008) Quandt, Alexander; Özdoğan, Cem; Ferrari, Maurizio; Speranza, Giorgio; 40569
We discuss a downsizing of optical components into the nanometer range. It presupposes the substitution of photons by ballistic electrons, but it also requires a simple and robust concept to assemble the analogues of basic electronic and optical components on such a tiny length scale. Here, one of the most promising candidate schemes employs graphene as a basic nanosubstrate. We elucidate the suggested behaviour of graphene as an electronic metamaterial [1], and show that other desired electronic or optical functionalities may be obtained through a patterning with sub-nanometer sized boron clusters [2].
Citation Count: Quandt, A...et al. (2008). Boron doped graphene nanostructures. Physica Status Solidi B Basic Solid State Physics, 245(10), 2077-2081. http://dx.doi.org/10.1002/pssb.200879559
Boron doped graphene nanostructures
(Wiley-Blackwell, 2008) Quandt, Alexander; Özdoğan, Cem; Kuntsmann, Jens; Fehske, Holger
We present results from an ab initio study of metallized semiconducting graphene nanostructures. Our model system consists of an alternating chain of quasi-planar B(7) clusters embedded into a semiconducting arm-chair nanoribbon. We observe the appearance of overlapping bands around the Fermi-level, with crystal momenta pointing into the direction of these boron chains. This observation could be a vantage point for the development of graphene nanodevices and integrated nanocircuits, based on existing technologies
Citation Count: Quandt, A., Özdoğan, C. (2010). Feynman, biominerals and graphene - Basic aspects of nanoscience. Communications In Nonlinear Science And Numerical Simulation, 15(6), 1575-1582. http://dx.doi.org/ 10.1016/j.cnsns.2009.06.009
Feynman, biominerals and graphene - basic aspects of nanoscience
(Elsevier Science Bv, 2010) Quandt, Alexander; Özdoğan, Cem
This article is about writing small. Inspired by R.P. Feynman's legendary talk There's plenty of room at the bottom, we recapitulate his famous Gedanken experiment of condensing a lot of useful information on the head of a pin [see Feymnan R, J. MEMS 1 (1992) 60]. These considerations will familiarize LIS with the length scales for a future downsizing of technological components, and they allow for some speculations about ultimate physical or chemical limits of the corresponding nanodevices. Furthermore we will analyze the nano-technological capabilities of Mother Nature in the case of magnetotactic bacteria, and briefly sketch the cornerstones of the rapidly growing field of biomineralization, which might open up a new science of complex functional nanomaterials in the near future. Finally we describe a general scheme to shrink integrated microelectronic circuits towards the very size limits of nanotechnology
Citation Count: Quandt, Alexander; Ozdogan, Cem; Kunstmann, Jens, "Functionalizing graphene by embedded boron clusters", Nanotechnology, Vol.19, No.33, (2008).
Functionalizing graphene by embedded boron clusters
(IOP Publishing LTD, 2008) Quandt, Alexander; Özdoğan, Cem; Kunstmann, Jens; Fehske, Holger; 40569
We present a model system that might serve as a blueprint for the controlled layout of graphene based nanodevices. The systems consists of chains of B-7 clusters implanted in a graphene matrix, where the boron clusters are not directly connected. We show that the graphene matrix easily accepts these alternating B-7-C-6 chains and that the implanted boron components may dramatically modify the electronic properties of graphene based nanomaterials. This suggests a functionalization of graphene nanomaterials, where the semiconducting properties might be supplemented by parts of the graphene matrix itself, but the basic wiring will be provided by alternating chains of implanted boron clusters that connect these areas.
Citation Count: Kuntsmann, J...et al. (2011). Stability of edge states and edge magnetism in graphene nanoribbons. Physical Review B, 83(4). http://dx.doi.org/10.1103/PhysRevB.83.045414
Stability of edge states and edge magnetism in graphene nanoribbons
(Amer Physical Soc, 2011) Kuntsmann, Jens; Özdoğan, Cem; Quandt, Alexander; Fehske, Holger
We critically discuss the stability of edge states and edge magnetism in zigzag edge graphene nanoribbons (ZGNRs). We point out that magnetic edge states might not exist in real systems and show that there are at least three very natural mechanisms-edge reconstruction, edge passivation, and edge closure-which dramatically reduce the effect of edge states in ZGNRs or even totally eliminate them. Even if systems with magnetic edge states could be made, the intrinsic magnetism would not be stable at room temperature. Charge doping and the presence of edge defects further destabilize the intrinsic magnetism of such systems