STM image (500 mV, 0.8 nA) of a 5-nm-wide graphene nanoribbon with armchair edge orientation (a) and STM image of a 6.5-nm-wide ribbon with edges of precisely zigzag orientation (300 mV, 2 nA) (b) patterned by scanning tunnelling lithography in a graphene sheet deposited on a Au(111) substrate. The circular insets show atomic-resolution STM images, confirming the crystallographic directions of the edges. The atomic-resolution images in the insets were Fourier filtered for clarity. The protrusions on the otherwise highly regular edges are imaging instabilities.

graphene nanoribbon

Experimental data reveal the emergence of magnetic order on edges of sub-10 nm graphene nanoribbons. Using a nanofabrication technique based on Scanning Tunneling Microscopy Lithography, graphene nanoribbons have been fabricated with nanometer precision and edges of well-defined crystallographic orientation. Ribbons with edges of so-called zigzag orientation display a sharp semiconductor-metal transition as a function of their width, which was identified as the signature of a magnetic switching from antiferromagnetic to ferromagnetic coupling between spin-polarized ribbon edges. Remarkably the edge magnetism was found to be stable at room temperature, raising hopes of graphene-based spintronic devices operating under ambient conditions.

http://www.nature.com/nature/journal/v514/n7524/full/nature13831.html

a, STM image (300×300 nm) of a reconstructed Cu(111) surface continuously covered by graphene. The rectangular protrusions are single-atom-height Cu adatom clusters, whereas the trench-like features correspond to vacancy islands with well-defined widths of 5 nm and oriented along three particular directions. b, High-resolution STM image of a nanotrench revealing the nanoscale periodic rippling of the graphene membrane suspended over the trench.

L. Tapaszto and coworkers realized subnanometre-wavelength periodic ripples of suspended graphene membranes. The observed nanorippling mode violates the predictions of the continuum model. Nevertheless, microscopic simulations based on a quantum mechanical description of the chemical binding accurately describe the observed rippling mode. The ability of graphene to ripple down to subnanometre wavelengths can be exploited in strain-engineering graphene-based nanoelectronic and nanoelectromechanical devices beyond the boundaries set by continuum mechanics.

http://www.nature.com/nphys/journal/v8/n10/full/nphys2389.html

Optical microscopy images (a,b) of MoS2 single layer areas (1L, outlined by dotted lines) with several hundreds of microns lateral size exfoliated on gold (Au 111) substrate. The flakes of blue color are thick MoS2 multilayers (ML). The large areas of the faintest optical contrast have been confirmed to be single layers by Raman spectroscopy (inset).

3

Isolating large-areas of atomically thin transition metal chalcogenide crystals is an important but challenging task. The mechanical exfoliation technique can provide single layers of the highest structural quality, enabling to study their pristine properties and ultimate device performance. However, a major drawback of the technique is the low yield and small (typically < 10 μm) lateral size of the produced single layers. Here, we report a novel mechanical exfoliation technique, based on chemically enhanced adhesion, yielding MoS2 single layers with typical lateral sizes of several hundreds of microns.

The idea is to exploit the chemical affinity of the sulfur atoms that can bind more strongly to a gold surface than the neighboring layers of the bulk MoS2 crystal. Moreover, we found that our exfoliation process is not specific to MoS2, but can be generally applied for various layered chalcogenides including selenites and tellurides, providing an easy access to large-area 2D crystals for the whole class of layered transition metal chalcogenides.

http://www.nature.com/articles/srep14714?WT.ec_id=SREP-639-20151013&spMailingID=49762212&spUserID=ODkwMTM2NjQzMgS2&spJobID=781723956&spReportId=NzgxNzIzOTU2S0

News

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris ut tellus vehicula urna semper tristique. Ut iaculis dui elit. Integer posuere vulputate nisi, sit amet[...]
Nulla vitae elit libero
December 15, 2014 | 2 Comments
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris ut tellus vehicula urna semper tristique. Ut iaculis dui elit. Integer posuere vulputate nisi, sit amet[...]
Vivamus sagittis lacus
December 15, 2014 | 2 Comments
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris ut tellus vehicula urna semper tristique. Ut iaculis dui elit. Integer posuere vulputate nisi, sit amet[...]
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris ut tellus vehicula urna semper tristique. Ut iaculis dui elit. Integer posuere vulputate nisi, sit amet[...]

Meet Our Teem

Levente Tapasztó

Levente Tapasztó

PhD
Principal Investigator, ERC Group Leader
Head of Nanostructures Department
Fellow of the European Academy of Sciences and Arts
tel.: +36-1-392 / 2680
Péter Nemes Incze

Péter Nemes Incze

PhD
Research Fellow
tel.: +36-1-3922222 / 1316
Péter Vancsó

Péter Vancsó

PhD (on leave at University of Namur)
Research Fellow
Gergely Dobrik

Gergely Dobrik

PhD
Postdoctoral Researcher
tel.: +36-1-3922222 / 1378
Gábor Zsolt Magda

Gábor Zsolt Magda

PhD student
Research Fellow
tel.: +36-1-3922222 / 1157
János Pető

János Pető

PhD student
+36-1-3922222 / 1157
Péter Kun

Péter Kun

PhD student
tel.: +36-1-3922222 / 1378
Orsolya Tapasztó

Orsolya Tapasztó

PhD
Postdoctoral Researcher / Dissemination
tel.: +36-1-3922222 / 3250