Quantum Materials & Nanoelectronics

Research on low-dimensional electron systems at surfaces and interfaces is essential for the development of novel types of nanoscale devices that exploit a range of electronic and magnetic effects. Two outstanding examples are carbon nanostructures (e.g., graphene) and topological insulators (e.g., Bi2Se3), which constitute the focus of our activities. With the aid of spectroscopic methods and electrical measurements, we thoroughly explore the (opto)electronic properties of these materials. In particular, we address their electronic structure in dependence of interfacial doping as well as (covalent or non-covalent) chemical functionalization. Of interest is also the possibility to lift the spin-degeneracy without the use of magnetic fields, as well as the interplay and coexistence of topologically trivial as well as non-trivial states. A further focus is on the synthesis, controlled manipulation and device incorporation of various one- and two-dimensional nanostructures, including inorganic semiconductor nanowires and graphene nanoribbons. Here the aim is to gain a deeper understanding of the basic operation principles of nanoscale photodetectors, photovoltaic devices and field-effect transistors. Along this direction, we probe the local photocurrent response at metal contacts or interfaces between different nanostructures. Another objective is to realize spintronic devices, for instance by implementing strong spin-splitting into a quantum well state, or hybridizing molecular magnets with carbon nanostructures.

 

Responsible Scientists

Dr. Christian Ast

Dr. Marko Burghard

 

Team Members

Christian Ast, Hadj M. Benia, Marko Burghard, Pascal Gehring, Alexander Hoyer, Eva Peters, Frieder Reusch, Roberto Urcuyo, Kristina Vaklinova

 

Key Publications

P. Gehring, H.M. Benia, Y. Weng, R. Dinnebier, C.R. Ast, M. Burghard, and K. Kern
A Natural Topological Insulator
Nano Lett. 13, 1179 (2013)
Article

Pascal Gehring, Bo F. Gao, Marko Burghard, Klaus Kern
Growth of high-mobility Bi2Te2Se nanoplatelets on BN sheets by van der Waals epitaxy
Nano Lett. 12, 5137 (2012)
Article

Hadj M. Benia, Chengtian Lin, Klaus Kern, and Christian R. Ast
Reactive chemical doping of the Bi2Se3 topological insulator
Phys. Rev. Lett. 107, 177602 (2011)
Article

Ravi S. Sundaram, Mathias Steiner, Hsin-Ying Chiu, Michael Engel, Ageeth A. Bol, Ralph Krupke, Marko Burghard, Klaus Kern, and Phaedon Avouris
Weak electronic coupling at the graphene-gold interface
Nano Letters 11, 3833 (2011)
Article

M. Burghard, H. Klauk, and K. Kern,
Carbon-based field effect transistors for nanoelectronics
Adv. Mater. 21, 2586 (2009)
Article

Isabella Gierz, Christian Riedl, Ulrich Starke, Christian R. Ast, and Klaus Kern
Atomic Hole Doping of Graphene
Nano Letters 8, 4603 (2008)
Article

E.J.H. Lee, K. Balasubramanian, R.T. Weitz, M. Burghard, and K. Kern,
Contact and edge effects in graphene devices
Nature Nanotechnology 3, 486 (2008)
Article

C. Gómez-Navarro, R.T. Weitz, A.M. Bittner, M. Scolari, A. Mews, M. Burghard, and K. Kern,
Electronic transport properties of individual chemically reduced graphene oxide sheets
Nano Letters 7, 3499 (2007)
Article

Christian R. Ast, Jürgen Henk, Arthur Ernst, Luca Moreschini, Mihaela C. Falub, Daniela Pacilé, Patrick Bruno, Klaus Kern, and Marco Grioni
Giant spin splitting through surface alloying
Phys. Rev. Lett. 98, 186807 (2007)
Article

 
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