scholarly journals ESPLORANDO “FLATLANDIA”: DAL GRAFENE ALLA SCOPERTA DI NUOVI MATERIALI BI-DIMENSIONALI

2020 ◽  
Author(s):  
Francesco Tumino
Keyword(s):  
Materials Science ◽  
2D Materials ◽  
Single Layer ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Bulk Materials ◽  
Molecular Sensing ◽  
Novel Technologies ◽  
Materials Research ◽  
First Time

The development of nanotechnology has encouraged the research of new nanomaterials for innovative applications. In 2004, the production and study of graphene — that is a single layer of carbon atoms — showed, for the first time, the extraordinary properties of this material and opened the way to the exploration of the so-called two-dimensional (2D) materials. Since then, several 2D materials have been produced and studied, revealing properties and behaviours, in general, very different from those of corresponding bulk materials. Research on 2D materials is nowadays one of the most active and promising fields of materials science, which is setting the basis for the development of novel technologies, such as in electronics, optoelectronics, energy and molecular sensing. In this paper, some important aspects of the study of 2D materials will be introduced — such as the synthesis methodologies and characterization techniques — and some of their properties will be shown, with the support of recent experimental results of scanning tunneling microscopy (STM) investigations.

A New, Nearly Single-Domain Surface Structure of Homoepitaxial Diamondr (001) Films

1996 ◽  
Vol 423 ◽  
Author(s):  
Yalei Kuang ◽  
Naesung Lee ◽  
Andrzej Badzian ◽  
Teresa Badzian ◽  
Tien T. Tsong
Keyword(s):  
Surface Structure ◽  
Natural Diamond ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Domain ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Plasma Chemical Vapor Deposition ◽  
Boron Doped ◽  
Step Edges

AbstractBoron-doped homoepitaxial diamond films were grown on natural diamond (001) substrates using microwave-assisted plasma chemical vapor deposition techniques. The surface structures were investigated using scanning tunneling microscopy (STM). This showed a dimertype 2×1 reconstruction structure with single-layer steps where dimer rows on the upper terrace are normal to or parallel to the step edges. We found that dimer rows parallel to the step edges are much longer than those normal to the step edges. The nearly single-domain surface structure observed by STM is in agreement with the low-energy electron diffraction (LEED) patterns from these surfaces. The high atomic resolution STM image showed that the local 1×1 configurations exist.

scholarly journals The effect of moiré superstructures on topological edge states in twisted bismuthene homojunctions

2020 ◽  
Vol 6 (23) ◽  
pp. eaba2773 ◽  
Author(s):  
Jian Gou ◽  
Longjuan Kong ◽  
Xiaoyue He ◽  
Yu Li Huang ◽  
Jiatao Sun ◽  
...  
Keyword(s):  
Single Layer ◽  
Scanning Tunneling ◽  
Edge States ◽  
First Principles Calculations ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Spatially Distributed ◽  
Topological States ◽  
Device Applications

Creating and controlling the topological properties of two-dimensional topological insulators is essential for spintronic device applications. Here, we report the successful growth of bismuth homostructure consisting of monolayer bismuthene and single-layer black phosphorus–like Bi (BP-Bi) on the HOPG surface. Combining scanning tunneling microscopy/spectroscopy with noncontact atomic force microscopy, moiré superstructures with twist angles in the bismuth homostructure and the modulation of topological edge states of bismuthene were observed and studied. First-principles calculations reproduced the moiré superlattice and indicated that the structure fluctuation is ascribed to the stacking modes between bismuthene and BP-Bi, which induce spatially distributed interface interactions in the bismuth homostructure. The modulation of topological edge states is directly related to the variation of interlayer interactions. Our results suggest a promising pathway to tailor the topological states through interfacial interactions.

Single-layer MoS2formation by sulfidation of molybdenum oxides in different oxidation states on Au(111)

2017 ◽  
Vol 19 (21) ◽  
pp. 14020-14029 ◽  
Author(s):  
Norberto Salazar ◽  
Igor Beinik ◽  
Jeppe V. Lauritsen
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Photoelectron Spectroscopy ◽  
Single Layer ◽  
Oxidation States ◽  
Scanning Tunneling ◽  
Molybdenum Oxides ◽  
Tunneling Microscopy ◽  
X Ray

The sulfidation pathway from MoO3to MoS2on Au(111) revealed by a combination of Scanning Tunneling Microscopy and X-Ray Photoelectron Spectroscopy.

Scanning Tunneling Microscopy Studies of the Initial Stages of Thin Film Growth: the Role of the Surface Dangling Bonds

1987 ◽  
Vol 105 ◽  
Author(s):  
Ph. Avouris ◽  
R. Wolkow ◽  
F. Bozso ◽  
R. J. Hamers
Keyword(s):  
Film Growth ◽  
Thin Film Growth ◽  
Scanning Tunneling ◽  
Reaction Products ◽  
Dangling Bonds ◽  
Surface Chemical Reaction ◽  
Tunneling Microscopy ◽  
Reacting Systems ◽  
First Time

AbstractWe present STM and photoemission studies of the reactions of Si(100)-(2×1) and Si(111)–(7×7) with NH3. STM allows us to image the occupied and unoccupied states of the reacting systems and to obtain electronic spectra with atomic lateral resolution. Thus, for the first time, a surface chemical reaction can be probed at the atomic level. We find that both surfaces are reactive even at 100K. However, both the extent of the reaction and the reaction products at 300K are different on the two surfaces. STM also shows that while surface dangling bonds are essential for low-temperature reactivity, not all triplycoordinated Si sites are chemically equivalent. On the 7×7 surface the rest-atoms are more reactive than center-adatoms which, in turn, are more reactive than corner-adatoms.

Surface-mediated spin dynamics probed by optical-pump–probe scanning tunneling microscopy

2019 ◽  
Vol 21 (14) ◽  
pp. 7256-7260 ◽  
Author(s):  
Zi-Han Wang ◽  
Cheul-Hyun Yoon ◽  
Shoji Yoshida ◽  
Yusuke Arashida ◽  
Osamu Takeuchi ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Materials Science ◽  
Spin Dynamics ◽  
Functional Materials ◽  
Surface Effects ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Optical Pump ◽  
Pump Probe

In current materials science and technologies, surface effects on carrier and spin dynamics in functional materials and devices are of great importance.

Twisted charge-density-wave patterns in bilayer 2D crystals and modulated electronic states

2D Materials ◽  
2021 ◽  
Author(s):  
Yaoyao Chen ◽  
Liwei Liu ◽  
Xuan Song ◽  
Han Yang ◽  
zeping Huang ◽  
...  
Keyword(s):  
Charge Density ◽  
Density Wave ◽  
Single Layer ◽  
Interlayer Coupling ◽  
Charge Density Waves ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Atomic Lattices ◽  
Fresh Insight ◽  
2D Crystals

Abstract The twistronics of the atomic-thick two-dimensional (2D) van der Waals materials has opened a new venue to investigate the interlayer coupling. Till now, most studies focus on the twist of atomic lattices and the resulted moiré superstructures, while the reports about the twist of charge density waves (CDW), the superstructures of which are from individual layers are limited. Here, using molecular beam epitaxy, we construct bilayer (BL) 1T-NbSe2 vertical structures. With high resolution scanning tunneling microscopy observations, we identify two cases of CDW twisted stacking with atomic precision. The typical twist angles are 0o and 60o between the 1st and the 2nd layer, although the top Se atomic lattices of these two layers are parallel. Compared to the single layer case, the dI/dV at BL shows an insulator-to-metal transition, with the Hubbard bands shrinking towards the Fermi level (EF ). More intriguingly, interlayer coupling states rise near EF , which are dependent on the CDW twist angles. These findings give fresh insight into the engineering of 2D materials by CDW twisting and are potentially applicable for future nanoelectronic devices.

scholarly journals Two-Dimensional Ordering of Solute Nanoclusters at a Close-Packed Stacking Fault: Modeling and Experimental Analysis

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Hajime Kimizuka ◽  
Shu Kurokawa ◽  
Akihiro Yamaguchi ◽  
Akira Sakai ◽  
Shigenobu Ogata
Keyword(s):  
Materials Science ◽  
Orientational Order ◽  
Stacking Fault ◽  
Coarse Grained ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Tunneling Microscopy ◽  
Solute Cluster ◽  
Entropic Effect ◽  
High Degree

Abstract Predicting the equilibrium ordered structures at internal interfaces, especially in the case of nanometer-scale chemical heterogeneities, is an ongoing challenge in materials science. In this study, we established an ab-initio coarse-grained modeling technique for describing the phase-like behavior of a close-packed stacking-fault-type interface containing solute nanoclusters, which undergo a two-dimensional disorder-order transition, depending on the temperature and composition. Notably, this approach can predict the two-dimensional medium-range ordering in the nanocluster arrays realized in Mg-based alloys, in a manner consistent with scanning tunneling microscopy-based measurements. We predicted that the repulsively interacting solute-cluster system undergoes a continuous evolution into a highly ordered densely packed morphology while maintaining a high degree of six-fold orientational order, which is attributable mainly to an entropic effect. The uncovered interaction-dependent ordering properties may be useful for the design of nanostructured materials utilizing the self-organization of two-dimensional nanocluster arrays in the close-packed interfaces.

FORMATION AND MODIFICATION OF MESOSCOPIC STRUCTURES ON GRAPHITE (HOPG) AND SILICON SURFACES BY MEANS OF SCANNING TUNNELING MICROSCOPY

1996 ◽  
Vol 03 (01) ◽  
pp. 961-967 ◽  
Author(s):  
R. CZAJKA ◽  
A. KASUYA ◽  
A. WAWRO ◽  
N. HORIGUCHI ◽  
Y. NISHINA
Keyword(s):  
Silicon Surfaces ◽  
Scanning Tunneling ◽  
Experimental Investigations ◽  
Rectangular Lattice ◽  
Tunneling Microscopy ◽  
Au Clusters ◽  
Lattice Arrangement ◽  
Scale Structures ◽  
First Time ◽  
Monolayer Coverage

This paper presents results of our experimental investigations of the adsorption and interaction of microclusters on some crystalline surfaces to form regular arrangements. Microclusters were produced and deposited up to a monolayer coverage on the c-plane of graphite (HOPG) or Si(111) substrates by thermal evaporation, laser ablation, or deposition from STM tip. A rectangular lattice arrangement of Se n(n=5–8) ring cluster has been fabricated for the first time on the HOPG. Also, arrays of Au clusters with a well-controlled diameter, desired periodicity, and size have been obtained by applying a sequence of voltage pulses between the STM tip and the substrate. A variety of carbon clusters have been produced by laser modification of C 60 fullerenes, and observed by means of scanning tunneling microscope (STM). Finally, various nanometer-scale structures have been modified by applying different bias voltages (between tip probe and sample) or induced by thermal treatment.

Sign in / Sign up

Export Citation Format

Share Document