Silicene, germanene and other group IV 2D materials

• Patrick Vogt

Beilstein J. Nanotechnol. 2018, 9, 2665–2667, doi:10.3762/bjnano.9.248

• Patrick Vogt Institut für Physik, Technische Universität Chemnitz, Reichenhainer Str. 70, Chemnitz, Germany 10.3762/bjnano.9.248 Keywords: 2D materials; germanene, silicene; The discovery of graphene and its tremendous impact on scientific research has initiated the search for other elemental

• concepts exploiting their topological properties. In recent years this search has lead to the discovery of other members of this family of 2D materials based on other group IV elements. In 2012 silicene was first synthesized under ultrahigh vacuum conditions on a silver(111) single crystal by Si molecular

• , which increases with increasing atomic size. As a consequence of this mixed hybridization, the bonds between adjacent atoms of the lattice are buckled, resulting in a layer that is not completely flat. Such buckling within the layer is illustrated in Figure 1 for different elemental 2D materials. For

Thickness-dependent photoelectrochemical properties of a semitransparent Co₃O₄ photocathode

• Malkeshkumar Patel and
• Joondong Kim

Beilstein J. Nanotechnol. 2018, 9, 2432–2442, doi:10.3762/bjnano.9.228

• ][43], and the third is the combination with a catalyst such as NiMo and transition-metal dichalcogenide 2D materials [43][44]. Conclusion We fabricated porous, semitransparent Co3O4 working electrodes of varying thickness using Kirkendall diffusion thermal oxidation in air. The thickness-dependent

Light–Matter interactions on the nanoscale

• Mohsen Rahmani and
• Chennupati Jagadish

Beilstein J. Nanotechnol. 2018, 9, 2125–2127, doi:10.3762/bjnano.9.201

• graphene with electromagnetic radiation is fascinating due to the two-dimensional confinement of electrons and the exceptional band structure of graphene. Graphene has a simple band structure with zero band gap, but its optical response is nontrivial. Subsequently, other two-dimensional (2D) materials

SO₂ gas adsorption on carbon nanomaterials: a comparative study

• Deepu J. Babu,
• Divya Puthusseri,
• Frank G. Kühl,
• Sherif Okeil,
• Michael Bruns,
• Manfred Hampe and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 1782–1792, doi:10.3762/bjnano.9.169

• shown that the oxygen functionalities present on GO are in the form of hydroxy and carboxy groups [12]. The tunability of the material in terms of porosity and extent of functionalization makes GO a prototype of a hydrophilic carbon adsorbent and as such interesting for studying gas adsorption in 2D

• materials. Carbon nanohorns (CNHs) have a tubular structure with a closed cone-tip structure at one end (Figure 1c). Individual CNHs are usually single-walled with an internal diameter of 2–4 nm. The unique characteristic of CNHs is the rigid spherically aggregated structure with diameters of 50–100 nm [19

Toward the use of CVD-grown MoS₂ nanosheets as field-emission source

• Geetanjali Deokar,
• Nitul S. Rajput,
• Junjie Li,
• Francis Leonard Deepak,
• Wei Ou-Yang,
• Nicolas Reckinger,
• Carla Bittencourt,
• Jean-Francois Colomer and
• Mustapha Jouiad

Beilstein J. Nanotechnol. 2018, 9, 1686–1694, doi:10.3762/bjnano.9.160

• ; molybdenum disulfide (MoS2); nanosheets; sulfurization; transmission electron microscopy (TEM); Introduction There is a great interest in the development of one- and two-dimensional (1D and 2D) materials for field-emission (FE) based cathodes using various nanostructured materials [1] for applications in

• displays, X-ray sources and cold-cathode electron sources [2]. 1D and 2D materials such as carbon nanotubes [3], ZnO nanorods [1], LaB6 nanowires [2], SnS2 nanosheets (NSs) [4], vertically aligned graphene [5], WS2 nanotubes [6], MoSe2 nanosheets [7], and MoS2 NSs [8][9][10] are potential field-emitter

• candidates. The FE properties depend on the microstructure of the materials, such as morphology, orientation, size and internal or intrinsic features [1]. Among the different morphologies of 1D and 2D materials, vertically aligned nanostructures are considered as good candidates for field emission. Due to

Free-radical gases on two-dimensional transition-metal disulfides (XS₂, X = Mo/W): robust half-metallicity for efficient nitrogen oxide sensors

• Chunmei Zhang,
• Yalong Jiao,
• Fengxian Ma,
• Sri Kasi Matta,
• Steven Bottle and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1641–1646, doi:10.3762/bjnano.9.156

• ], composites of nanoflower-like CuxO and multilayer graphene (CuMGCs) [5] have been successfully synthesized as new types of room-temperature NO gas sensors. Compared with 3D materials [6], two-dimensional (2D) materials (sheets with thickness of on atom) [7][8][9][10][11][12][13][14][15] such as graphene [8

The electrical conductivity of CNT/graphene composites: a new method for accelerating transmission function calculations

• Olga E. Glukhova and
• Dmitriy S. Shmygin

Beilstein J. Nanotechnol. 2018, 9, 1254–1262, doi:10.3762/bjnano.9.117

• Olga E. Glukhova Dmitriy S. Shmygin Saratov State University, Saratov, Russian Federation 10.3762/bjnano.9.117 Abstract We present a new universal method to accelerate calculations of transmission function and electrical conductance of 2D materials, the supercell of which may contain hundreds or

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

• Sri Kasi Matta,
• Chunmei Zhang,
• Yalong Jiao,
• Anthony O'Mullane and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1247–1253, doi:10.3762/bjnano.9.116

• suitable for photovoltaic applications, such as excellent visible light absorption, favorable exciton formation, and charge separation are equally essential for two-dimensional (2D) materials. Here, we systematically study 2D group IV–V compounds such as SiAs2 and GeAs2 with regard to their structural

• . Furthermore, band-gap tuning is also possible by application of tensile strain. Our results highlight a new family of 2D materials with great potential for solar cell applications. Keywords: density functional theory (DFT); photovoltaic applications; solar cell; two-dimensional semiconductors; Introduction

• The potential applications of two-dimensional (2D) materials are one of the key research areas for many researchers since graphene was isolated and characterized in 2004 [1]. The number of applications is vast including photovoltaics, nanoelectronics, Dirac materials and solar fuels through water

Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

Beilstein J. Nanotechnol. 2018, 9, 1194–1199, doi:10.3762/bjnano.9.110

• quasiparticles, a class of hybrid systems where Majorana states appear around 2D vortex cores in the bulk and on the external edges of the sample [16]. Another class of 2D materials with propagating Majorana modes are the topological insulators based on the quantum-anomalous Hall effect. We refer, specifically

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• surface potential changes on the hybrid system. In summary, interface-induced organized structures atop 2D materials may have an important impact on both design and operation of π-conjugated nanomaterial-based hybrid systems. Keywords: DFT calculations; graphene; organic semiconductors; scanning probe

• , photomodification of graphene-RA interfacial dipole, surface band bending and others [39][40][41][42][43][44][45]. An analysis of the exact contribution of each mechanism might be very complex and is out of the scope of the present work. The realization of RA SAMs atop other 2D materials and its subsequent

• estimated via Raman scattering experiment is of order of 1013 cm−2, consistent with the value predicted from ab initio calculations. Conclusion Organic semiconductor dyes and 2D materials are classes of materials which have enormous potential applications by themselves. The possibility of creating hybrid

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

• Ying Wang,
• Yue Shen,
• Xingya Wang,
• Zhiwei Shen,
• Bin Li,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 900–906, doi:10.3762/bjnano.9.84

• studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar

Valley-selective directional emission from a transition-metal dichalcogenide monolayer mediated by a plasmonic nanoantenna

• Haitao Chen,
• Mingkai Liu,
• Lei Xu and
• Dragomir N. Neshev

Beilstein J. Nanotechnol. 2018, 9, 780–788, doi:10.3762/bjnano.9.71

• structure. Conclusion: The scheme we propose here can potentially serve as an important component for valley-based applications, such as non-volatile information storage and processing. Keywords: 2D materials, multipolar emission; nanoantenna; plasmonic; transition-metal dichalcogenides; valley

Sensing behavior of flower-shaped MoS₂ nanoflakes: case study with methanol and xylene

• Maryam Barzegar,
• Masoud Berahman and
• Azam Iraji zad

Beilstein J. Nanotechnol. 2018, 9, 608–615, doi:10.3762/bjnano.9.57

• Maryam Barzegar Masoud Berahman Azam Iraji zad Nanotechnology Research Institute, Sharif University of Technology, Tehran, Iran Physics Department, Sharif University of Technology, Tehran, Iran 10.3762/bjnano.9.57 Abstract Recent research interest in two-dimensional (2D) materials has led to an

• emerging new group of materials known as transition metal dichalcogenides (TMDs), which have significant electrical, optical, and transport properties. MoS2 is one of the well-known 2D materials in this group, which is a semiconductor with controllable band gap based on its structure. The hydrothermal

• functional theory; gas sensor; hydrothermal method; methanol; MoS2 nanoflakes; xylene vapor; Introduction Recent efforts in exploring two-dimensional (2D) materials have led to the introduction of a new family of materials known as transition metal dichalcogenides (TMDs), which show remarkable electrical

Design of photonic microcavities in hexagonal boron nitride

• Sejeong Kim,
• Milos Toth and
• Igor Aharonovich

Beilstein J. Nanotechnol. 2018, 9, 102–108, doi:10.3762/bjnano.9.12

• presented in this work will pave a way to a broad range of applications enabled by integrated photonic circuits based on 2D materials. Funding Financial support from the Australian Research Council (DE130100592, DP140102721), the Asian Office of Aerospace Research and Development grant FA2386-17-1-4064 are

Patterning of supported gold monolayers via chemical lift-off lithography

• Liane S. Slaughter,
• Kevin M. Cheung,
• Sami Kaappa,
• Huan H. Cao,
• Qing Yang,
• Thomas D. Young,
• Andrew C. Serino,
• Sami Malola,
• Jana M. Olson,
• Stephan Link,
• Hannu Häkkinen,
• Anne M. Andrews and
• Paul S. Weiss

Beilstein J. Nanotechnol. 2017, 8, 2648–2661, doi:10.3762/bjnano.8.265

• ]. We have used CLL on gold to control the placement and nanoscale environment around surface-immobilized biomolecules and to simplify patterning steps in device fabrication [1][2][7][8][9][10][11][12][13]. Two-dimensional (2D) materials have proven to be extremely rich in terms of new and potentially

Localized growth of carbon nanotubes via lithographic fabrication of metallic deposits

• Fan Tu,
• Martin Drost,
• Imre Szenti,
• Janos Kiss,
• Zoltan Kónya and
• Hubertus Marbach

Beilstein J. Nanotechnol. 2017, 8, 2592–2605, doi:10.3762/bjnano.8.260

• for future investigation is the fabrication of EBID seed structures with different geometries to trigger novel carbon nanostructures such as “twisted rope” structures or extended 2D materials. Experimental The EBID and AG processes were carried out in a commercial UHV system (Multiscanlab, Scienta

Amplified cross-linking efficiency of self-assembled monolayers through targeted dissociative electron attachment for the production of carbon nanomembranes

• Sascha Koch,
• Christopher D. Kaiser,
• Paul Penner,
• Michael Barclay,
• Lena Frommeyer,
• Daniel Emmrich,
• Patrick Stohmann,
• Tarek Abu-Husein,
• Andreas Terfort,
• D. Howard Fairbrother,
• Oddur Ingólfsson and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2017, 8, 2562–2571, doi:10.3762/bjnano.8.256

• ) verified the existence of a mechanically stable CNM created from 2-I-BPT after exposure to an electron dose as low as 1.8 mC/cm2. In contrast, SAMs made from BPT, 2-Cl-BPT and 2-Br-BPT did not form stable CNMs after a significantly higher electron dose of 9 mC/cm2. Keywords: 2D materials; carbon

Optical contrast and refractive index of natural van der Waals heterostructure nanosheets of franckeite

• Patricia Gant,
• Foad Ghasemi,
• David Maeso,
• Carmen Munuera,
• Elena López-Elvira,
• Riccardo Frisenda,
• David Pérez De Lara,
• Gabino Rubio-Bollinger,
• Mar Garcia-Hernandez and
• Andres Castellanos-Gomez

Beilstein J. Nanotechnol. 2017, 8, 2357–2362, doi:10.3762/bjnano.8.235

• of high quality two-dimensional (2D) materials [1]. This sample fabrication process, however, typically yields randomly distributed flakes over the substrate surface with a large distribution of flake areas and thicknesses. Therefore fast, reliable, and non-destructive screening methods are crucial

• nanosheets by optical microscopy. Franckeite is one of the latest novel layered materials added to the 2D materials family and up to now very little is known about this material [15][16][17][18]. One of the special characteristics that triggered the interest of the community on franckeite is the fact that it

• values because they are the most common SiO2 thicknesses in the research of graphene and other 2D materials. Prior to the study of the optical properties of the franckeite nanosheets, we experimentally verify the thickness of the SiO2 capping layers of each employed substrate by means of reflectance

Intercalation of Si between MoS₂ layers

• Rik van Bremen,
• Qirong Yao,
• Soumya Banerjee,
• Deniz Cakir,
• Nuri Oncel and
• Harold J. W. Zandvliet

Beilstein J. Nanotechnol. 2017, 8, 1952–1960, doi:10.3762/bjnano.8.196

• -dimensional materials; Introduction Since the discovery of graphene [1][2][3][4] interest has extended to the search for other 2D materials with properties similar to graphene. One appealing candidate is silicene, a graphene-like 2D allotrope of silicon. The first calculations of graphite-like allotropes of

Coexistence of strongly buckled germanene phases on Al(111)

• Weimin Wang and
• Roger I. G. Uhrberg

Beilstein J. Nanotechnol. 2017, 8, 1946–1951, doi:10.3762/bjnano.8.195

• model. Keywords: core-level spectroscopy; DFT; germanene; STM; Introduction The properties of two-dimensional (2D) materials are currently subjected to intense experimental and theoretical studies. The research is focused on many important properties predicted by theory for various conceivable 2D

• materials. In similarity with graphene, some other materials are also predicted to show a linear electron dispersion near the Fermi level. Other important properties/phenomena that make 2D materials particularly interesting for incorporation in various devices are, magnetism, superconductivity, Rashba type

• spin-splitting, quantum spin Hall effect, amongst others. Based on the wealth of physical phenomena exhibited by various 2D materials, they are considered as important future materials of high potential for applications in nano-scale electronics and spintronics. A sub-group of 2D materials is graphene

α-Silicene as oxidation-resistant ultra-thin coating material

• Ali Kandemir,
• Fadil Iyikanat,
• Cihan Bacaksiz and
• Hasan Sahin

Beilstein J. Nanotechnol. 2017, 8, 1808–1814, doi:10.3762/bjnano.8.182

• intensively in surface protection for a long time [1][2], two-dimensional (2D) materials have become new candidates for nanoscale coatings for different material groups. Therefore, coating mechanisms at the nanoscale take are of high interest in nanotechnology, and new candidates for nanostructural protection

(Metallo)porphyrins for potential materials science applications

• Lars Smykalla,
• Carola Mende,
• Michael Fronk,
• Pablo F. Siles,
• Michael Hietschold,
• Georgeta Salvan,
• Dietrich R. T. Zahn,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1786–1800, doi:10.3762/bjnano.8.180

• allow for the engineering of manifold extended 2D materials with novel transport properties. One major approach for surface-confined polymerization is the halogen-based Ullmann coupling reaction [42]. Thereby, the topography and also electronic properties of the covalent organic framework are determined

Adsorption and diffusion characteristics of lithium on hydrogenated α- and β-silicene

• Fadil Iyikanat,
• Ali Kandemir,
• Cihan Bacaksiz and
• Hasan Sahin

Beilstein J. Nanotechnol. 2017, 8, 1742–1748, doi:10.3762/bjnano.8.175

• barriers show that α- and β-silicene are promising platforms for Li-storage applications. Keywords: density functional theory; diffusion; Li atom; silicene; ultra-thin materials; Introduction Following the first synthesis of graphene, the family of two-dimensional (2D) materials have drawn extraordinary

• chalcogenides [18]. Structural stability, chemical versatility and electronic band gaps of 2D materials that cover the range from 0 to 5 eV make them attractive for current nanoscale device applications. In the large family of 2D materials, silicene deserves a special consideration due to its compatibility and

• for the hydrogenated forms of α- and β-silicene on a Ag(111) surface. The adsorption of alkali metal atoms provides various ways to modify the structural, electronic and magnetic properties of 2D materials. It was found that adsorption of alkali atoms is a proper way to dope carbon nanotubes

Group-13 and group-15 doping of germanane

• Nicholas D. Cultrara,
• Maxx Q. Arguilla,
• Shishi Jiang,
• Chuanchuan Sun,
• Michael R. Scudder,
• R. Dominic Ross and
• Joshua E. Goldberger

Beilstein J. Nanotechnol. 2017, 8, 1642–1648, doi:10.3762/bjnano.8.164

• layered van der Waals materials [20][21][22]. Germanane, a hydrogen-terminated graphane analogue of germanium, has garnered considerable attention in the field of 2D materials on account of its direct band gap [5][23][24], large predicted electron mobility, and the ability to controllably tune the

Two-dimensional carbon-based nanocomposites for photocatalytic energy generation and environmental remediation applications

• Suneel Kumar,
• Ashish Kumar,
• Ashish Bahuguna,
• Vipul Sharma and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2017, 8, 1571–1600, doi:10.3762/bjnano.8.159

• that nanocomposite formation of semiconductors with such 2D materials effectively improves the photocatalytic processes. In addition, these 2D materials possess several extraordinary properties, which makes them more advantageous over other materials as summarized below [39]: high specific surface area

• . Carbon-based 2D materials Graphene Since the discovery of graphene in 2004, it has attracted great attention because of its fascinating electrical, thermal, optical and mechanical properties. Basically, graphene consists of a single layer of sp2 hybridized carbon atoms densely packed into an atomically

• leads to the efficient separation of the photogenerated charge carriers and thereby enhances the visible light photocatalytic H2 production activity of the nanocomposite. As discussed in the introduction section regarding the significance of 2D materials in photocatalytic applications, Chen et al. [147