Morphology-driven gas sensing by fabricated fractals: A review

• Vishal Kamathe and
• Rupali Nagar

Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88

• , carbon monoxide, ammonia, nitrous oxide, and ethanol (Figure 10e,f) at 250 °C. The estimated fractal dimensions were 1.82 for the pore network and 1.72 for the foam sensor. Titanium oxide-based fractals Fusco et al. modified dielectric titanium oxide (TiO2) nanoparticles with fractal structure with a

• ethanol, acetone, and toluene, was examined. The LSPR sensor showed a 4–8 times higher sensitivity for detecting gas molecules with the fractal-enhanced dielectric structure. The enhancement in the sensitivity was mainly attributed to the large surface-to-volume ratio of fractal system, which resulted in

• deposited on an antenna, and a microwave transduction principle was employed for gas sensing. In these measurements, the interaction of the gas analyte with the sensor was studied at different frequencies and changes in the reflection coefficient and dielectric properties of sensing material were observed

Irradiation-driven molecular dynamics simulation of the FEBID process for Pt(PF₃)₄

• Alexey Prosvetov,
• Alexey V. Verkhovtsev,
• Gennady Sushko and
• Andrey V. Solov’yov

Beilstein J. Nanotechnol. 2021, 12, 1151–1172, doi:10.3762/bjnano.12.86

• without fragmentation of the molecule. On this basis, one concludes that almost every ionizing collision leads to fragmentation; hence, the DI cross section can be approximated by the total ionization cross section. The latter can be calculated by means of the dielectric formalism [46] as it was done in

Open-loop amplitude-modulation Kelvin probe force microscopy operated in single-pass PeakForce tapping mode

• Gheorghe Stan and
• Pradeep Namboodiri

Beilstein J. Nanotechnol. 2021, 12, 1115–1126, doi:10.3762/bjnano.12.83

• voltage, CPD the contact potential difference between the AFM probe and sample, and CF the capacitive factor depending on the geometry and dielectric properties of the system. Expressions of CF are obtained from the detailed calculation of the electrostatic force between the AFM probe and sample [67][68

First-principles study of the structural, optoelectronic and thermophysical properties of the π-SnSe for thermoelectric applications

• Muhammad Atif Sattar,
• Najwa Al Bouzieh,
• Maamar Benkraouda and
• Noureddine Amrane

Beilstein J. Nanotechnol. 2021, 12, 1101–1114, doi:10.3762/bjnano.12.82

• , the computation of the optical properties is decreased towards the assessment of the response function, which is called dielectric tensor or polarizability. For practical optoelectronics applications, it is essential to investigate the optical response of the π-SnSe alloy. For this purpose, we have

• used the independent particle approximation (IPA) implemented by the optics module of WIEN2k, which computes the direct transitions through Kohn and Sham (KS) [70] eigenvalues between occupied and unoccupied states [71]. For the first step, a complex dielectric function ε(ω), which depends on the

• frequency and comprises all the details of the optical response, is determined through the following relation [72]: where ε1(ω) and ε2(ω) represent the real and imaginary parts of the dielectric function, respectively. The absorptive imaginary ε2(ω) component can be determined by calculating the matrix

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• . Among others, ultrathin dielectric layers of either alkali halides (e.g., NaCl [17]) or metal oxides (e.g., MgO [18], Al2O3 [19], and CuO [20]), or nitrides (CuN [21]) have been shown to be beneficial for successfully reducing or even completely switching off the unwanted interaction between the metal

• dielectric layers on top of the surface [34][35] or a chemical modification of the surface to saturate the dangling bonds. In surface-science-based studies, for the latter approach hydrogenation of semiconductor surfaces is frequently applied as effective passivation against chemisorption of adsorbates [36

• changing chemical environment. Next, we outline articles that use 2D materials and ultrathin dielectric layers as decoupling layers. While on the one hand, molecular functionalization is a powerful approach to tune the electronic and optical properties of 2D materials, in particular for many practical

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

High-yield synthesis of silver nanowires for transparent conducting PET films

• Gul Naz,
• Hafsa Asghar,
• Muhammad Ramzan,
• Muhammad Arshad,
• Rashid Ahmed,
• Muhammad Bilal Tahir,
• Bakhtiar Ul Haq,
• Nadeem Baig and
• Junaid Jalil

Beilstein J. Nanotechnol. 2021, 12, 624–632, doi:10.3762/bjnano.12.51

• circuit including a white LED was utilized. Results and Discussion To determine the morphology, the as-prepared silver nanostructures were first characterized by UV–vis absorption spectroscopy. The absorption spectrum of AgNWs is a function of the dielectric material, the chemicals used, and the particle

Impact of GaAs(100) surface preparation on EQE of AZO/Al₂O₃/p-GaAs photovoltaic structures

• Piotr Caban,
• Rafał Pietruszka,
• Jarosław Kaszewski,
• Monika Ożga,
• Bartłomiej S. Witkowski,
• Krzysztof Kopalko,
• Piotr Kuźmiuk,
• Katarzyna Gwóźdź,
• Ewa Płaczek-Popko,
• Krystyna Lawniczak-Jablonska and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 578–592, doi:10.3762/bjnano.12.48

• negative impact on the performance of GaAs-based microelectronic and optoelectronic devices [10][11]. Therefore, in order to take advantage of the properties of gallium arsenide [12], its interface with a dielectric or other semiconductor partner must be carefully prepared. This can be obtained either by

• the removal of the native oxide layer followed by an adequate surface passivation technique [13] and/or by a proper choice of the dielectric and its deposition method. Regarding the dielectric, the most common ones are aluminum oxide (Al2O3) and hafnium dioxide (HfO2) for which the preferable

• fabricated devices. The initial illustrative model of the device presented the deposited Al2O3 passivation coating as a separate dielectric film (Figure 2). However, according to the XPS analysis results (Table 1) one can see that the Al2O3 deposited within five ALD cycles does not constitute a separate

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• - and few-layer thick graphene films [1][2]. Unique properties, such as high thermal stability and conductivity, immense intra-sheet stiffness, and excellent dielectric properties, make h-BN interesting for technological applications. For example, thin films of h-BN have been used as a passivating layer

• non-contact atomic force microscopy (nc-AFM) to study h-BN on Cu(111). This template has interesting properties because the dielectric layer is only very weakly bound to the metal and shows an electronically induced Moiré superstructure [25][26]. First STM studies on this system pointed to only a

• originate from a locally varying charge transfer between the substrate and the dielectric layer [38][39][40]. In our studied substrate, it is the lattice mismatch between h-BN and the Cu(111) substrate that leads to a varying atomic registry and subsequently induces a lateral modulation of the charge

Simulation of gas sensing with a triboelectric nanogenerator

• Kaiqin Zhao,
• Hua Gan,
• Huan Li,
• Ziyu Liu and
• Zhiyuan Zhu

Beilstein J. Nanotechnol. 2021, 12, 507–516, doi:10.3762/bjnano.12.41

• rectangles represent the triboelectric materials with different dielectric constants. The length and width are set as 50 mm and 0.1 mm, respectively. By changing the distance (ds), we simulate the process of the triboelectric materials approaching and moving away from each other. Figure 3a is the surface

• the two dielectric materials varies, the field intensity caused by the charge also varies. The corresponding electric potential decreases with decreasing distance and increases with increasing distance. Figure 3b is the electric potential distribution diagram when the distance is 0.1 mm. In the

• simulation, we measured the potential difference between the outer surfaces of the two dielectric materials as ds is gradually increased from 0.1 to 1 mm, as shown in Figure 3c, which also reflects the influence of the distance between the two triboelectric materials on the potential. In practice, it is

Colloidal particle aggregation: mechanism of assembly studied via constructal theory modeling

• Scott C. Bukosky,
• Sukrith Dev,
• Monica S. Allen and
• Jeffery W. Allen

Beilstein J. Nanotechnol. 2021, 12, 413–423, doi:10.3762/bjnano.12.33

• layers result in repulsion between two particles, this force is constantly opposed by the attractive van der Waals force. The balance between these interparticle forces gives the total DLVO force and highly depends on system parameters, such as the electrolyte concentration and fluid dielectric constant

• dielectric constant, respectively. Conversely, the attractive van der Waals force is given by [14]: where the characteristic energy scale is set by the Hamaker constant, A. It is noted that Equation 1 and Equation 2 assume spherical particles of equal radius and a sufficiently small separation distance (a

• lattice arrangements are shown in Figure 5 and Figure 6, respectively. The total DLVO forces from both uniform (left) and non-uniform (right) aggregation are plotted as functions of particle spacing or particle radius and electrolyte concentration or fluid dielectric constant. The same general trends were

Structural and optical characteristics determined by the sputtering deposition conditions of oxide thin films

• Petronela Prepelita,
• Florin Garoi and
• Valentin Craciun

Beilstein J. Nanotechnol. 2021, 12, 354–365, doi:10.3762/bjnano.12.29

• ; optical quality; SiO2 and ZnO; structural properties; thin films; Introduction The application of oxide thin films is quite diverse due to their excellent properties [1][2][3][4][5], such as dielectric properties [6][7][8] for the production of metamaterials [9]. Metamaterials applied in the field of

• space science come with a new dimension of microstructural representation of advanced functional materials [10][11]. Metamaterial structures are of significant interest not only in space science but also in the fields of public security and sensors [9][10][11]. Materials with dielectric properties, such

• others. Among the important applications of these oxides are materials with dielectric properties used in the fabrication of metasurface structures, transparent conductive oxides and buffer layers used in solar cells, and materials used in sensor technology [6][8][17][18][19][20][21]. Materials with

Paper-based triboelectric nanogenerators and their applications: a review

• Jing Han,
• Nuo Xu,
• Yuchen Liang,
• Mei Ding,
• Junyi Zhai,
• Qijun Sun and
• Zhong Lin Wang

Beilstein J. Nanotechnol. 2021, 12, 151–171, doi:10.3762/bjnano.12.12

• polarization direction, TENGs can have four working modes [87], including vertical contact–separation (CS) mode, in-plane lateral-sliding (LS) mode, single-electrode (SE) mode, and freestanding triboelectric-layer (FT) mode, as shown in Figure 2a. In the vertical CS mode, a stack of two dielectric films is

• plated with a metal electrode at the back surface of each layer. When the two dielectric films are vertically separated and periodically contacted due to the application of external forces, a small air gap is formed in the middle and a potential difference is induced between the two electrodes, which can

• ground and taken as the reference electrode. The direction of the induced electric field can be reversely changed during the approximation or separation between the bottom electrode and the upper dielectric materials. The charge exchange will occur between the bottom electrode and ground to balance the

Mapping the local dielectric constant of a biological nanostructured system

• Wescley Walison Valeriano,
• Rodrigo Ribeiro Andrade,
• Juan Pablo Vasco,
• Angelo Malachias,
• Bernardo Ruegger Almeida Neves,
• Paulo Sergio Soares Guimarães and
• Wagner Nunes Rodrigues

Beilstein J. Nanotechnol. 2021, 12, 139–150, doi:10.3762/bjnano.12.11

• work is to determine the varying dielectric constant of a biological nanostructured system via electrostatic force microscopy (EFM) and to show how this method is useful to study natural photonic crystals. We mapped the dielectric constant of the cross section of the posterior wing of the damselfly

• Chalcopteryx rutilans with nanometric resolution. We obtained structural information on its constitutive nanolayers and the absolute values of their dielectric constant. By relating the measured profile of the static dielectric constant to the profile of the refractive index in the visible range, combined with

• optical reflectance measurements and simulation, we were able to describe the origin of the strongly iridescent wing colors of this Amazonian rainforest damselfly. The method we demonstrate here should be useful for the study of other biological nanostructured systems. Keywords: dielectric constant

Bulk chemical composition contrast from attractive forces in AFM force spectroscopy

• Dorothee Silbernagl,
• Media Ghasem Zadeh Khorasani,
• Natalia Cano Murillo,
• Anna Maria Elert and
• Heinz Sturm

Beilstein J. Nanotechnol. 2021, 12, 58–71, doi:10.3762/bjnano.12.5

• turn generate oscillating dipoles in an adjacent body. The response of a specific material in an oscillating electromagnetic field E(f) is described by the dielectric constant εr(f) which can be extracted from the absorption spectrum of the material. Hence, how materials (e.g., the sample (S) and the

• tip (T)) interact in a medium (m) is defined by the difference in the dielectric responses. The Hamaker coefficient AHam can be derived from the relative differences of the dielectric constant εS(f), εT(f), and εm(f), summed up over all the frequencies at which the fluctuations can occur (UV–vis–IR

Kondo effects in small-bandgap carbon nanotube quantum dots

• Patryk Florków,
• Damian Krychowski and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2020, 11, 1873–1890, doi:10.3762/bjnano.11.169

• effects of interaction play a more fundamental role. Carbon nanotubes are quasi one-dimensional systems, and the role of correlations further increases in quantum dots due to additional confinement. Of importance is also the low dielectric constant, which is especially low in suspended nanotubes [36]. A

Mapping of integrated PIN diodes with a 3D architecture by scanning microwave impedance microscopy and dynamic spectroscopy

• Rosine Coq Germanicus,
• Peter De Wolf,
• Florent Lallemand,
• Catherine Bunel,
• Serge Bardy,
• Hugues Murray and
• Ulrike Lüders

Beilstein J. Nanotechnol. 2020, 11, 1764–1775, doi:10.3762/bjnano.11.159

• ) (doped semiconducting layers) and “back end of line” (BEOL) layers (metallization, trench dielectric, and isolation) of highly integrated microelectronic devices. Based on atomic force microscopy, an electromagnetically shielded and electrically conductive tip is used in scanning microwave impedance

• monolithic silicon integrated PIN diode with a 3D architecture. The studied device includes FEOL regions (doped semiconductors and oxides) and “back end of line” (BEOL) regions (metallic and dielectric layers). After the presentation of the results, the capabilities of the sMIM mode are discussed in detail

• second area of interest was the bottom of a deep trench (area 2 in Figure 2). Deep trenches were fabricated by dry etching pores with a high aspect ratio and a diameter of 1 µm. During the FEOL processing, trenches were filled with a dielectric layer, followed by an in situ highly phosphorus-doped

Absorption and photoconductivity spectra of amorphous multilayer structures

• Oxana Iaseniuc and
• Mihail Iovu

Beilstein J. Nanotechnol. 2020, 11, 1757–1763, doi:10.3762/bjnano.11.158

• , Nt is the concentration of traps, e is the electron charge, µ is the drift mobility, ε is the dielectric constant, t = Δ/(kBT) (Δ is the parameter of the trap distribution, kB is the Boltzmann constant, T is the absolute temperature), V is the applied voltage, and d is the sample thickness. The

Out-of-plane surface patterning by subsurface processing of polymer substrates with focused ion beams

• Serguei Chiriaev,
• Luciana Tavares,
• Vadzim Adashkevich,
• Arkadiusz J. Goszczak and
• Horst-Günter Rubahn

Beilstein J. Nanotechnol. 2020, 11, 1693–1703, doi:10.3762/bjnano.11.151

• for the fabrication of a range of microoptical and microfluidic devices and microelectromechanical systems (MEMS). Possible applications of the method for microoptical devices are discussed in detail in our previous work [4]. They include tuning the thickness of the dielectric layer in the metal

The influence of an interfacial hBN layer on the fluorescence of an organic molecule

• Christine Brülke,
• Oliver Bauer and
• Moritz M. Sokolowski

Beilstein J. Nanotechnol. 2020, 11, 1663–1684, doi:10.3762/bjnano.11.149

• that the energy of the SPP of Cu(111), which is calculated from the condition [51] using the dielectric functions given in [52], is obtained at a value of = 2.3 eV. Our excitation energy was 2.698 eV. From our experiment we have indeed evidence that SERS is related to surface defects. This will be

• a dominant role of the dielectric properties of the metal substrates for the transition energies. The peak FLC (cf. Figure 4b) shows the same behavior as FLB at a coverage of 1.55 ML. It is as broad as FLB and appears after annealing at 200 K. However, it is not present at a coverage of 0.60 ML

Amorphized length and variability in phase-change memory line cells

• Nafisa Noor,
• Sadid Muneer,
• Raihan Sayeed Khan,
• Anna Gorbenko and
• Helena Silva

Beilstein J. Nanotechnol. 2020, 11, 1644–1654, doi:10.3762/bjnano.11.147

• -switching process and not to the permanent and detrimental electrical breakdown failure that occurs in any dielectric material. Experimental The patterned GST-225 line cells used for this study were deposited on silicon dioxide (SiO2), had bottom metal contact pads (tungsten with Ti/TiN liner), and were

Fabrication of nano/microstructures for SERS substrates using an electrochemical method

• Jingran Zhang,
• Tianqi Jia,
• Xiaoping Li,
• Junjie Yang,
• Zhengkai Li,
• Guangfeng Shi,
• Xinming Zhang and
• Zuobin Wang

Beilstein J. Nanotechnol. 2020, 11, 1568–1576, doi:10.3762/bjnano.11.139

• , all PEO-treated Mg specimens demonstrate the typical surface morphology, which comprises of micrometer and sub-micrometer-sized quasi-circular pores and cracks. This porous and uneven surface is a result of the consecutive dielectric breakdown of the passivation layer and the heat generated during

Electrokinetic characterization of synthetic protein nanoparticles

• Daniel F. Quevedo,
• Cody J. Lentz,
• Adriana Coll de Peña,
• Yazmin Hernandez,
• Nahal Habibi,
• Rikako Miki,
• Joerg Lahann and
• Blanca H. Lapizco-Encinas

Beilstein J. Nanotechnol. 2020, 11, 1556–1567, doi:10.3762/bjnano.11.138

• can also exploit differences in both electrical charge and dielectric properties of the particles, making them uniquely suited methods to process and purify SPNPs. EK techniques can also be used to differentiate between SPNPs and ASPNPs, since the anisotropic particles, the polar ends of which have

• dielectric properties of particles can be exploited for the design of EK-based separation processes. These results demonstrate that EK microfluidics is a promising technique to be used for the characterization and separation of synthetic protein nanoparticles. Theoretical Approach Depending on the magnitude

Optically and electrically driven nanoantennas

• Monika Fleischer,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2020, 11, 1542–1545, doi:10.3762/bjnano.11.136

• . However, owing to the polarization and far-field interference, a silencing of the SHG is observed for decreasing gap sizes [53]. This effect is further studied in [54] using the surface integral equation method. On the other hand, the generation of higher harmonics by a dielectric nanostructure can be

Controlling the electronic and physical coupling on dielectric thin films

• Philipp Hurdax,
• Michael Hollerer,
• Larissa Egger,
• Georg Koller,
• Xiaosheng Yang,
• Anja Haags,
• Serguei Soubatch,
• Frank Stefan Tautz,
• Mathias Richter,
• Alexander Gottwald,
• Peter Puschnig,
• Martin Sterrer and
• Michael G. Ramsey

Beilstein J. Nanotechnol. 2020, 11, 1492–1503, doi:10.3762/bjnano.11.132

• ), 10587 Berlin, Germany 10.3762/bjnano.11.132 Abstract Ultrathin dielectric/insulating films on metals are often used as decoupling layers to allow for the study of the electronic properties of adsorbed molecules without electronic interference from the underlying metal substrate. However, the presence

• : decoupling; integer charge transfer; organic films; para-sexiphenyl; thin dielectric film; Introduction Since the first scanning tunneling microscope (STM) imaging of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of pentacene (5A) on NaCl/Cu(111) was

• performed [1], the concept of decoupling molecules from metal substrates with large bandgap dielectric films has become widely accepted. Although such systems have become a rich field of research, particularly in the scanning probe microscopy community, it is often forgotten that the wide bandgap insulating