Nanoelectronic Components Research Articles

Model and performance analysis of energy conversion in functionally graded flexoelectric semiconductor nanostructures

Energy systems converting efficiently from surrounding environment for powering semiconductor electronic components at nanoscale has attracted intense research interests. Due to the strong size dependency, flexoelectricity has been demonstrated as an excellent candidate implemented as nanoscale piezoelectric semiconductor energy harvesters. In this work, through a judicious exploitation of structural symmetry and nonuniformity, we theoretically study the energy conversion behaviors of a novel asymmetric nanodisk model composed of functionally graded (FG) flexoelectric semiconductor (FS) (FG-FS) materials while being loaded with thickness-extensional mechanical vibration. In numerical analysis, the material parameters have been treated with a general variation method under the Cartesian coordinate systems for simplicity. Taking into accounts of the nonuniform structural form and multi-field coupling features, we derived an octic governing equation with variable coefficients for the current analyzed FG-FS nanodisk structure, which is, however, almost impossible to obtain analytical solutions. To successfully address this issue and also further explore the improved performance and new phenomena induced by the FG type of non-uniform structural profile, we specially proposed an efficient tensor algorithm and reduced the octic governing equation into one quartic equation with variable coefficients and other four common quadratic equations. Later, we explicitly explored the effect of each physical parameter on the energy conversion performance of the FS energy harvester by studying the variations of the output electric power density and the energy conversion efficiency. Results illustrated that the electromechanical energy conversion behaviors of the studied FG-FS nanodisk can be properly tuned by not only the related material parameters but also their gradations. We believe our work have the potential to pave new way for the designs and manufacture of novel nano-electronic semiconductor components for the future practical applications.

On-Surface Synthesis of Polyene-Linked Porphyrin Cooligomer.

π-Conjugated molecules are viewed as fundamental components in forthcoming molecular nanoelectronics in which semiconducting functional units are linked to each other via metallic molecular wires. However, it is still challenging to construct such block cooligomers on the surface. Here, we present a synthesis of [18]-polyene-linked Zn-porphyrin cooligomers via a two-step reaction of the alkyl groups on Cu(111) and Cu(110). Nonyl groups (-C9H19) substituted at the 5,15-meso positions of Zn-porphyrin were first transformed to alkenyl groups (-C9H10) by dehydrogenation. Subsequently, homocoupling of the terminal -CH2 groups resulted in the formation of extended [18]-polyene-linked porphyrin cooligomers. The structures of the products at each reaction step were investigated by bond-resolved scanning tunneling microscopy at low temperatures. A combination of angle-resolved photoemission spectroscopy and density functional theory calculations revealed the metallic property of the all trans [18]-polyene linker on Cu(110). This finding may provide an approach to fabricate complex nanocarbon structures on the surface.

(Invited) Integration of Functional Nanostructures and Nanoparticles into Micro- and Nanoelectronic Components and Systems

In recent decades, there has been a significant evolution of microelectronic and semiconductor technologies towards the nanoscale. Both bottom-up and top-down integration concepts of functional nanostructures and nanoparticles into micro- and nanofabricated electronic components have become critical issues that decisively affect the performance of smart electronic systems in various application areas such as environmental sensing and energy harvesting.Functional nanostructures and nanoparticles of different shapes, sizes, morphologies, and materials are now used in various technical and industrial applications, medicine, pharmacy, biology, electronics, power engineering, ecology, and many other fields. However, the complex engineering challenge here is the integration of functional nanostructures, such as molecular components (e.g., functional self-assembled molecular monolayers or entities of desoxyribonucleic acid, DNA), organic or inorganic nanoparticles (metal, semiconductor, colloidal materials), or similar building blocks into nanolithographically fabricated environments.Manufacturing paradigms for this integration go beyond current CMOS- and MEMS-fabrication schemes. Scale-bridging and hybrid manufacturing schemes that combine established top-down manufacturing techniques for microelectronic devices, including aspects of nanotechnology, with bottom-up nanoassembly of molecules on unstructured and pre-structured substrates are required. Microsystems technology based on the combination of conventional semiconductor processing with biotechnological approaches has thus become an emerging field with manifold applications, especially in the field of sensor technology.This contribution describes two illustrative and innovative research questions in nanopatterning and system integration at the micro-nano-interface to motivate applications with new and unprecedented functionalities. The first research question focuses on network-based biocomputing (NBC) using biological agents driven by biomolecular motor proteins in a lithographically fabricated nanofluidic channel system. This approach opens up opportunities for energy-efficient solutions to complex mathematical problems as they make their way through the NBC network. Methods are required to create switchable and rewritable nano-networks to address different mathematical problems using a single NBC-chip. Therefore, stimuli-responsive materials must be selectively and locally deposited into the nano-network to control the transport of the filaments through the network.The second research question focuses on nanophotonic devices based on DNA origami. The high-precision arrangement of nanoscopic substructures using specific binding sites (capture ends) of the DNA origami enables the precise arrangement of DNA origami functionalized with individualized metal nanoparticles. This arrangement could be used to exploit individual spectral response mediated by plasmonic effects.From a technological perspective, top-down lithographic nanostructuring technologies and bottom-up nanostructuring technologies are the basis for new device concepts. The adaptability of nanostructures to the world of biological molecules and other nanoscopic building blocks such as quantum dots and nanoparticles enables novel, even personalized, devices and engineering solutions.

Electron transport in a stressed moiré bigraphene structure

Within the framework of density functional theory in combination with the method of nonequilibrium Green's functions, the transport characteristics (band structure, transmission spectrum, current–voltage characteristic, and differential conductivity) of unstressed, stressed, and strongly stressed moiré bigraphene nanodevices with interlayer distances of 3.4 Å, 2.85 Å, and 1.7 Å, respectively, and consisting of two layers of graphene, where one of the layers is connected to electrodes (active graphene) and the other layer is electrically neutral (passive graphene) have been determined. It is established that, when passive graphene is twisted to certain angles before the moiré pattern is obtained (∼4° and ∼ 12°), the energy gap is opened, the value of range 1.66–1.82 eV and 3.78–4.69 eV in the unstressed state (in the stressed state 2.27–2.67 eV and 4.28–4.93 eV), respectively. It is shown that the transmission spectrum of bilayer graphene has features in the form of peak structures; with decreasing intergraphene distance these structures begin to blur and their quasiperiodic behavior is partially broken. The current–voltage characteristic of such nanostructures has areas with negative differential conductivity. Such nonlinear behavior of transport characteristics of bigraphene moiré structures can be used for the construction of electronic components of nanoelectronics on their basis.

Heavy Water Reduces the Electronic Conductance of Protein Wires via Deuteron Interactions with Aromatic Residues.

Proteins are versatile, self-assembling nanoelectronic components, but their hopping conductivity is expected to be influenced by solvent fluctuations. The role of the solvent was investigated by measuring the single molecule conductance of several proteins in both H2O and D2O. The conductance of a homologous series of protein wires decreases more rapidly with length in D2O, indicating a 6-fold decrease in carrier diffusion constant relative to the same protein in H2O. The effect was found to depend on the specific aromatic amino acid composition. A tryptophan zipper protein showed a decrease in conductance similar to that of the protein wires, whereas a phenylalanine zipper protein was insensitive to solvent changes. Tryptophan contains an indole amine, whereas the phenylalanine aromatic ring has no exchangeable protons, so the effect of heavy water on conductance is a consequence of specific D- or H-interactions with the aromatic residues.

Surface plasmon-mediated enhanced field electron emission based on metasurfaces with a nano-gap driven by LEDs

Vacuum electronic devices have the advantages of no scattering, anti-irradiation, and extreme operating temperatures. With their superiorities, light-assisted field emission can be utilized to drive ultrafast micro-/nano-vacuum electronic devices. However, traditional multiphoton or optical field emission is limited by the access of the lasers with high power and energy. In this Letter, an asymmetric non-semiconductor nanostructure may be applied to reduce cost with a nano-level gas or vacuum channel. We find that the basic LED may be a candidate to enhance the electron emission current by utilizing the multi-stage field enhancement consisting of tip effects and plasmon-based enhancement. By designing a field electron emission device with LEDs in standard atmospheric environment, we realize a 25% increase in field electron emission current at the resonance frequency with the light intensity under W cm−2 and the voltage less than 5 V. By comparing with lasers, simple LEDs are beneficial to increase the scope of applications with low-energy requirements. Meanwhile, the structure paves the way to the application of microelectronic and nano-electronic components in the on-chip electronic devices, such as switches and modulators.

Subnanometer-Wide Indium Selenide Nanoribbons.

Indium selenides (InxSey) have been shown to retain several desirable properties, such as ferroelectricity, tunable photoluminescence through temperature-controlled phase changes, and high electron mobility when confined to two dimensions (2D). In this work we synthesize single-layer, ultrathin, subnanometer-wide InxSey by templated growth inside single-walled carbon nanotubes (SWCNTs). Despite the complex polymorphism of InxSey we show that the phase of the encapsulated material can be identified through comparison of experimental aberration-corrected transmission electron microscopy (AC-TEM) images and AC-TEM simulations of known structures of InxSey. We show that, by altering synthesis conditions, one of two different stoichiometries of sub-nm InxSey, namely InSe or β-In2Se3, can be prepared. Additionally, in situ AC-TEM heating experiments reveal that encapsulated β-In2Se3 undergoes a phase change to γ-In2Se3 above 400 °C. Further analysis of the encapsulated species is performed using X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), and Raman spectroscopy, corroborating the identities of the encapsulated species. These materials could provide a platform for ultrathin, subnanometer-wide phase-change nanoribbons with applications as nanoelectronic components.

From defect to effect: controlling electronic transport in chevron graphene nanoribbons

While bottom-up synthesis allows for precise control over the properties of graphene nanoribbons (GNRs), the use of certain precursor molecules can result in edge defects, such as missing benzene rings that resemble a ‘bite’. We investigate the adverse effect of the ‘bite’ defects on the electronic transport properties in three chevron-type GNRs and discover that the extent of scattering is governed by the different defect positions. Applying the concepts learned in single GNRs, we engineer defects in two nanostructures to construct prototypical components for nanoelectronics. First, we design a switch, consisting of three laterally fused fluorenyl-chevron GNRs, and place a pair of ‘bite’ defects to effectively allow the switching between four binary states corresponding to distinct current pathways. Second, we show that conscientious placement of a ‘bite’ defect pair can increase conductance between two leads in a triple chevron GNR junction. Overall, we outline how the incorporation of ‘bite’ defects affects transport properties in chevron-type nanostructures and provide a guide on how to design nanoelectronic components.

Nanobionics-Driven Synthesis of Molybdenum Oxide Nanosheets with Tunable Plasmonic Resonances in Visible Light Regions.

Nanobionics-driven synthesis offers a process of designing and synthesizing functional materials on a nanoscale based on the structures and functions of biological systems. An approach such as this is environmentally friendly and sustainable, providing a viable option for synthesizing functional nanomaterials for catalysis and nanoelectronic components. In this work, we present a facile and green nanobionics approach to synthesize plasmonic HxMoO3 by interacting chloroplasts extracted from spinach with two-dimensional (2D) MoO3 nanoflakes. The generated plasmon resonances can be modulated in the visible wavelength ranges, and the efficiency to form the plasmonic materials is enhanced by 90% within 45 min of light excitation compared to reactions without chloroplast involvement. Such a characteristic is ascribed to the interfacial carrier dynamics between the two entities in the reactions, in which highly doped metal oxides with quasi-metallic properties can be formed to generate optical absorptions in the visible light region. The green synthesized plasmonic materials show high photocatalytic activities without the coupling of semiconductors, providing a promising nanoelectronics unit, based on the nanobionics-driven synthesized plasmonic materials.

Nano Quantum Computing thin films electronic components to act as rectifier and amplifier in simulation theory

There is an urgent need for cheap, high capacity, and high-speed electronic chips. This needs using Nano electronic components which obey quantum laws. Using Schrodinger equation, the solution for Nano rectangular plates or medium shows the possibility of rectifying and amplifying the electric current. When one fuses two rectangular metallic plates with one have dimensions less than a critical value while the dimension of the other is more than this critical value, one can rectify the electric current. It is also possible to rectify the electric current when two mediums are fused together. One must have an internal potential greater than a certain critical value, while the potential of the other is less than this critical value. Current amplification is possible also when the medium potential is less than the same critical value.

SnO2 Nanofibers Network for Cold Cathode Applications in Vacuum Nanoelectronics

AbstractField‐emission cold cathodes are the key components of vacuum nanoelectronics that offer great advantages over other electron sources based on the thermionic or photoelectric effects. In the effort to realize new electron sources, a systematic investigation of the field emission (FE) properties of SnO2 nanofiber networks is performed. High‐purity SnO2 nanofibers, confirmed by X‐ray photoelectron spectroscopy, are prepared by electrospinning technique and then uniformly distributed over Si wafer. Field emission properties are investigated using a nanomanipulated tip‐shaped anode, inside a scanning electron microscope, for fine tuning the anode‐cathode separation distance. A field‐emission current is observed with an applied electric field as low as 25 V μm−1. Performance parameters such as turn‐on field and field enhancement factor are evaluated within the theoretical Fowler–Nordheim framework as a function of the anode–cathode separation distance, demonstrating that a maximum enhancement factor of about 150 is obtained at a separation of 200 nm. The emission from a single nanofiber is characterized by a current saturation at high voltages that can be explained in terms of electron supply limitation within conduction band. No evidence of field emission current contribution by electron tunneling from the valence band is observed in the experimental data.

2D-Mo3S4 phase as promising contact for MoS2

The search for electrode materials for two-dimensional structures, particularly for semiconducting H-MoS2, is a significant problem for contemporary materials science. This stimulates interest in metastable structures, which motivates us to look at non-stoichiometric metastable states known as Berthollides. An unbiased evolutionary search for new two-dimensional structures in Mo-S system showed the presence of Mo5S4, Mo3S4, and MoS metastable structures (located near the decomposition line) in the low-sulfur area of phase diagram. The predicted novel Cm-Mo3S4 phase exhibits metallic properties and dynamic stability confirmed by the calculation of phonon dispersion spectra. Its lattice parameters are similar to the semiconducting H-MoS2 phase which makes it possible to use Cm-Mo3S4 as a conducting contact in nanodevices based on MoS2. A study of proposed H-MoS2/Cm-Mo3S4 lateral heterostructures showed that in the contact region a transition to the conducting states of the H-MoS2 edge atoms is observed, as well as the preservation of Cm-Mo3S4 conducting properties. The main feature of Cm-Mo3S4 is that it can be structurally obtained by a direct transition of H-MoS2 monolayer with sulfur vacancies. As a result, the predicted Cm-Mo3S4 phase is a promising candidate for conducting contacts in nanoelectronic device components.

Light‐Induced Solid‐State Protrusion of Gold Nanowires and Their Derivatives for Sensing Applications

AbstractGold nanowires (AuNWs) have been one of the key components for nanoelectronics and optoelectronic devices but the fabrication has been poorly customized for this purpose even though diverse synthetic strategies bloomed over the last decades. Here, the concept of light‐induced protrusion of AuNWs directly from solid state substrate is demonstrated, which is highly compatible for on‐chip fabrication of functional nanodevices. This is realized by irradiating the Au ion‐doped titanium dioxide (TiO2) films with continuous wave laser. The blue laser triggers the reduction and nucleation of Au(0) which grows vertically into AuNW bundles with diffusion‐controlled supply of Au ions within the TiO2 matrix. Thus, the morphology of the AuNWs can be tuned with irradiation time/power as well as the ion concentration, which can derive into Au nanorings (NRs) and NR stacks in 1D photonic crystal with reduced plasmon linewidth. Such light‐induced protrusion can also generate nanopillars by introducing Au seeds before irradiation. The surface‐enhanced Raman scattering performance of the AuNW bundles is excellent with fm detection limit. Such laser‐directed solid‐state growth technique is facile, versatile, cost‐effective site‐selective, ligand‐free, and wafer‐scalable, which opens up many promising applications in (bio)chemical sensing, photovoltaics, photocatalysis, plasmonic displays, and integrated nanoelectronic/optoelectronic devices.

Group three nitride clusters as promising components for nanoelectronics

The real use of nanoelectronics with organic molecules as a replacement of conventional silicon technology faces many challenges because of complications in synthesis and fabrication processes, short stability, junction breakdown, large fabrication costs and environmental influences. The present work aims at proposing a novel alternative by studying the potential of ‘inorganic analogues of the organic components' in molecular electronics. In comparison to their organic counterparts, the higher structural rigidity in inorganic components provides a possible added value in being less susceptible to environmental influences. The structure as well as electronic and transport properties of group three nitride analogues of benzene molecules, namely, the X3N3H6 (X = B, Al and Ga) clusters are analysed and compared with benzene and with melamine, a graphitic carbon nitride (g-C3N4) material. A detailed density functional theory (DFT) investigation is performed for the structural and electronic properties, whereas a combined DFT and non-equilibrium Green's function approach is used for the transport properties. The electron delocalisation with overlapping electronic states, the influence of magnetic fields and favourable quantum chemical properties of Ga3N3H6 clusters make the man outstanding electronic component for future nanoelectronics applications.

Tailored nano-electronics and photonics with two-dimensional materials at terahertz frequencies

The discovery of graphene and its fascinating capabilities has triggered an unprecedented interest in inorganic two-dimensional (2D) materials. van der Waals layered materials such as graphene, hexagonal boron nitride, transition metal dichalcogenides, and the more recently re-discovered black phosphorus (BP) indeed display an exceptional technological potential for engineering nano-electronic and nano-photonic devices and components “by design,” offering a unique platform for developing new devices with a variety of “ad hoc” properties. In this Perspective article, we provide a vision on the key transformative applications of 2D nanomaterials for the development of nanoelectronic, nanophotonic, optical, and plasmonic devices at terahertz frequencies, highlighting how the rich physical phenomena enabled by their unique band structure engineering can allow them to boost the vibrant field of quantum science and quantum technologies.

Silver Nanowire Synthesis and Strategies for Fabricating Transparent Conducting Electrodes.

One-dimensional metal nanowires, with novel functionalities like electrical conductivity, optical transparency and high mechanical stiffness, have attracted widespread interest for use in applications such as transparent electrodes in optoelectronic devices and active components in nanoelectronics and nanophotonics. In particular, silver nanowires (AgNWs) have been widely researched owing to the superlative thermal and electrical conductivity of bulk silver. Herein, we present a detailed review of the synthesis of AgNWs and their utilization in fabricating improved transparent conducting electrodes (TCE). We discuss a range of AgNW synthesis protocols, including template assisted and wet chemical techniques, and their ability to control the morphology of the synthesized nanowires. Furthermore, the use of scalable and cost-effective solution deposition methods to fabricate AgNW based TCE, along with the numerous treatments used for enhancing their optoelectronic properties, are also discussed.

АНАЛИЗ ДИНАМИЧЕСКИХ ПРОЦЕССОВ В НАНОЭЛЕКТРОННЫХ СТРУКТУРАХ НА БАЗЕ МЕМРЕЗИСТИВНЫХ ЭЛЕМЕНТОВ

The emergence of recently a wide range of nanoelectronic components is expanding the possibilities of information and computing systems. First of all, it concerns supercomputers with Petaflopovaya productivity. To achieve such performance on the basis of modern microelectronic devices, computing complexes are created, combining up to 100 thousand processors that consume about 100 megawatts of electrical energy and occupy about 300 square meters. A significant increase in productivity, reduction of energy consumption and a decrease in mass-dimensional indicators can be ensured in the transition from microelectronic to a nanoelectronic element base. For such promising nanoelectronic components include memristors. A memristor (from memory — memory, and resistor-electrical resistance) is a passive element in microelectronics that can change its resistance depending on the charge flowing through it. For a long time, the memristor was considered a theoretical model [7], which cannot be implemented in practice, until the first sample of the element demonstrating the properties of the memristor was created in 2008 by a team of scientists led by R. S. Williams in the research laboratory of Hewlett-Packard. The device does not store charge like a capacitor, does not support magnetic flux like an inductor. The change in the properties of the device is provided by chemical reactions in a thin two-layer film of titanium dioxide (5 nm). One layer of the device film is slightly depleted of oxygen and oxygen vacancies migrate between the layers when the voltage changes. This implementation of the memristor belongs to the class of nanoion devices. The observed phenomenon of hysteresis in the memristor allows it to be used, among other things, as a memory cell [9, 10-15, 20-21]. The already studied properties of memristors allow us to say that on their basis it is possible to create computers of a fundamentally new architecture, significantly exceeding semiconductor ones in performance. Due to the regular structure of intersecting nanowires, memristor fabrication is quite simple, especially in comparison with the complex structure of modern processors based on CMOS technology. As a result, the write / read time in the memristor memory cell does not exceed 5 ns. The number of read / write cycles exceeds 1012, and the storage time of information is more than 10 years. All this suggests that memristor memory will become the only type of computer memory. However, the use of such elements in real-life conditions leads to the fact that the electrical parameters of these devices vary over a wide range. This uncertainty in characteristics complicates circuit analysis and the entire design process for electronic devices that include memristor components. In this regard, the problem of assessing the stability of nanoelectronic structures based on memresistive elements under conditions of uncertain external influences is urgent.

Features of the development of a mathematical model of an electric multipole with memresistive branches for nanoelectronic components of quantum computing systems

The article discusses the features of constructing a mathematical model of a memristor, one of the components of quantum computing systems, in the finite increments of its parameters. A modification of the basic set of elements for the design of nanoelectronic circuits with the addition of a memristor as one of the components is described. As a result of the modification, a mathematical model of an electric multipole with memresistive branches in the finite increments of its parameters is constructed.

Desafíos de confiabilidad en dispositivos y circuitos nano-electrónicos de radiofrecuencia

Las tecnologías de integración de circuitos nanoelectrónicos basadas en silicio se acercan al límite de su evolución. La introducción de nuevos materiales para los dispositivos de efecto de campo, incluyendo óxidos de alta constante dieléctrica y semiconductores de alta movilidad, presenta enorme potencial para la próxima generación de componentes nanoelectrónicos, en donde uno de los principales desafíos a afrontar es su confiabilidad. A su vez, el impacto de la degradación de los óxidos delgados a nivel de circuitos complejos cobra gran importancia a medida que las aplicaciones se vuelven más complejas y sus condiciones de trabajo más exigentes. En este trabajo se presenta una recolección de algunos resultados obtenidos en el área de confiabilidad con una visión integral del problema, proponiendo explicaciones físicas de la degradación en dispositivos nanoelectrónicos novedosos y generando estrategias para garantizar el desempeño de circuitos de radiofrecuencia frente al envejecimiento.

A Chemically Soldered Polyoxometalate Single‐Molecule Transistor

AbstractPolyoxometalates have been proposed in the literature as nanoelectronic components, where they could offer key advantages with their structural versatility and rich electrochemistry. Apart from a few studies on their ensemble behaviour (as monolayers or thin films), this potential remains largely unexplored. We synthesised a pyridyl‐capped Anderson–Evans polyoxometalate and used it to fabricate single‐molecule junctions, using the organic termini to chemically “solder” a single cluster to two nanoelectrodes. Operating the device in an electrochemical environment allowed us to probe charge transport through different oxidation states of the polyoxometalate, and we report here an efficient three‐state transistor behaviour. Conductance data fits a quantum tunnelling mechanism with different charge‐transport probabilities through different charge states. Our results show the promise of polyoxometalates in nanoelectronics and give an insight on their single‐entity electrochemical behaviour.