ACS Appl. Mater. Interfaces 8,9337 (2016)
We present a method to create and erase spatially resolved doping profiles in graphene-hexagonal boron nitride heterostructures. The technique is based on photoinduced doping by a focused laser beam and does neither require masks nor photoresists. This makes our technique interesting for rapid prototyping of unconventional electronic device schemes, where the spatial resolution of the rewritable, long-term stable doping profiles is limited by only the laser spot size (≈600 nm) and the accuracy of sample positioning. Our optical doping method offers a way to implement and to test different, complex doping patterns in one and the very same graphene device, which is not achievable with conventional gating techniques.

Scientific Reports 6, 23547 (2016)
Hexagonal boron nitride (h-BN) is a promising material for implementation in spintronics due to a large band gap, low spin-orbit coupling, and a small lattice mismatch to graphene and to close-packed surfaces of fcc-Ni(111) and hcp-Co(0001). Epitaxial deposition of h-BN on ferromagnetic metals is aimed at small interface scattering of charge and spin carriers. We report on the controlled growth of h-BN/Ni(111) by means of molecular beam epitaxy (MBE). Structural and electronic properties of this system are investigated using cross-section transmission electron microscopy (TEM) and electron spectroscopies which confirm good agreement with the properties of bulk h-BN. The latter are also corroborated by density functional theory (DFT) calculations, revealing that the first h-BN layer at the interface to Ni is metallic. Our investigations demonstrate that MBE is a promising, versatile alternative to both the exfoliation approach and chemical vapour deposition of h-BN.

Luca F. Banszerus, Stephan Engels, and Michael Schmitz from our group have been awarded the "JARA Excellent Junior 2015" for their joint work on „Ultrahigh-mobility graphene devices from chemical vapor deposition on reusable copper“. For more information please see: www.jara.org.

For more information please see http://www.vi-ti.de/vi-ti/EN/Events/Workshop-Aachen-2016/Aachen-2016_node.html

Congrats on the group performance at the IWEPNM 2016 fun ski race. Jan Dauber took second place and Jens Sonntag took the third place. [Btw: Christoph Stampfer was fasted, just 1.33 seconds faster than Marc Drögeler (2nd fastest)].

Michael Schmitz won the 1st poster prize and Jens Sonntag won the 3rd poster prize at the "Graphene Study 2016" in Les Houches (France). Congratulations!

Nano Lett. 16, 1387 (2016)
We report on ballistic transport over more than 28 µm in graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride. The structures are fabricated by an advanced dry van-der-Waals transfer method and exhibit carrier mobilities of up to three million cm²/(Vs). The ballistic nature of charge transport is probed by measuring the bend resistance in cross- and square-shaped devices. Temperature dependent measurements furthermore prove that ballistic transport is maintained exceeding 1 µm up to 200 K.