Applications In Nanoelectronics Research Articles

Emergent Dirac Fermions in Epitaxial Planar Silicene Heterostructure.

Silicene, a single layer of Si atoms, shares many remarkable electronic properties with graphene. So far, silicene has been synthesized in its epitaxial form on a few surfaces of solids. Thus, the problem of silicene-substrate interaction appears, which usually depresses the original electronic behavior but may trigger properties superior to those of bare components. We report the direct observation of robust Dirac-dispersed bands in epitaxial silicene grown on Au(111) films deposited on Si(111). By performing in-depth angle-resolved photoemission spectroscopy measurements, we reveal three pairs of one-dimensional bands with linear dispersion running in three different directions of an otherwise two-dimensional system. By combining these results with first-principles calculations, we explore the nature of these bands and point to strong interaction between subsystems forming a complex Si-Au heterostructure. These findings emphasize the essential role of interfacial coupling and open a unique materials platform for exploring exotic quantum phenomena and applications in future-generation nanoelectronics.

Giant manipulation of thermal conductivity anisotropy in black phosphorene under external electric fields.

The thermal anisotropy of materials holds significant theoretical and practical implications in the domains of thermal transport and thermoelectricity. Black phosphorene, a novel two-dimensional (2D) semiconductor, is notable for its exceptional chemical and physical properties, attracting substantial attention for its thermal transport characteristics. Similar to other 2D materials, black phosphorene exhibits pronounced in-plane thermal anisotropy. Given its expanding applications in nanoelectronics, optoelectronics, and thermoelectrics, there is a growing need to manipulate its anisotropic thermal transport. Current methods for adjusting anisotropy or isotropy typically involve structural engineering or materials processing, which are often costly, time-consuming, and irreversible. In contrast, little progress has been made with methods that are intact, robust, and reversible. Driven by the intrinsic relationship between interatomic interaction-mediated phonon transport and electronic charges, we conduct a comprehensive investigation into the impact of an external electric field on the thermal transport properties of 2D black phosphorene using first-principles calculations and the phonon Boltzmann transport equation. Our findings reveal that applying an electric field in the Zigzag direction reduces the lattice thermal conductivity of black phosphorene, with the Zigzag direction being more responsive to the electric field than the Armchair direction. By adjusting the electric field to a maximum of E(f_xx) = 0.2 V Å-1, the anisotropic thermal conductivity of black phosphorene decreases by more than 28%, demonstrating effective manipulation of anisotropy. This significant transition in anisotropic thermal transport arises from the substantial reduction in thermal conductivity along the Zigzag direction at moderate electric field strengths. The underlying cause of this variation in anisotropy can be attributed to changes in group velocity, with the phonon lifetime serving as a scaling factor for reducing anisotropy. Analysis of the electronic structures shows that stronger electric fields induce more charges, enhancing the screening effect. The electric field significantly alters thermal conductivity by affecting bond ionicity and anharmonicity. Our study introduces a robust approach for tuning the anisotropy of phonon transport in materials using an external electric field, without altering the atomic structure, thus offering considerable advantages for applications in nanoelectronics and thermoelectric energy conversion.

Magnetic Nanostructure for Zigzag Graphene Nanoribbons and Application in Nano Electronics

Magnetic Nanostructure for Zigzag Graphene Nanoribbons and Application in Nano Electronics

Exfoliation of a metal-organic framework enabled by post-synthetic cleavage of a dipyridyl dianthracene ligand.

The synthetic tunability and porosity of two-dimensional (2D) metal-organic frameworks (MOFs) renders them a promising class of materials for ultrathin and nanoscale applications. Conductive 2D MOFs are of particular interest for applications in nanoelectronics, chemo-sensing, and memory storage. However, the lack of covalency along the stacking axis typically leads to poor crystallinity in 2D MOFs, limiting structural analysis and precluding exfoliation. One strategy to improve crystal growth is to increase order along the stacking direction. Here, we demonstrate the synthesis of mechanically exfoliatable macroscopic crystals of a 2D zinc MOF by selective dimensional reduction of a 3D zinc MOF bearing a dianthracene (diAn) ligand along the stacking axis. The diAn ligand, a thermally cleavable analogue of 4,4'-bipyridine, is synthesized by the direct functionalization of dianthraldehyde in a novel "dianthracene-first" approach. This work presents a new strategy for the growth of macroscopic crystals of 2D materials while introducing the functionalization of dianthraldehyde as a means to access new stimuli-responsive ligands.

Large piezoelectric responses and ultra-high carrier mobility in Janus HfGeZ3H (Z = N, P, As) monolayers: a first-principles study.

Breaking structural symmetry in two-dimensional layered Janus materials can result in enhanced new phenomena and create additional degrees of piezoelectric responses. In this study, we theoretically design a series of Janus monolayers HfGeZ3H (Z = N, P, As) and investigate their structural characteristics, crystal stability, piezoelectric responses, electronic features, and carrier mobility using first-principles calculations. Phonon dispersion analysis confirms that HfGeZ3H monolayers are dynamically stable and their mechanical stability is also confirmed through the Born-Huang criteria. It is demonstrated that while HfGeN3H is a semiconductor with a large bandgap of 3.50 eV, HfGeP3H and HfGeAs3H monolayers have narrower bandgaps being 1.07 and 0.92 eV, respectively. When the spin-orbit coupling is included, large spin-splitting energy is found in the electronic bands of HfGeZ3H. Janus HfGeZ3H monolayers can be treated as piezoelectric semiconductors with the coexistence of both in-plane and out-of-plane piezoelectric responses. In particular, HfGeZ3H monolayers exhibit ultra-high electron mobilities up to 6.40 × 103 cm2 V-1 s-1 (HfGeAs3H), indicating that they have potential for various applications in nanoelectronics.

Advances in nanofluidic field-effect transistors: external voltage-controlled solid-state nanochannels for stimulus-responsive ion transport and beyond.

Ion channels, intricate protein structures facilitating precise ion passage across cell membranes, are pivotal for vital cellular functions. Inspired by the remarkable capabilities of biological ion channels, the scientific community has ventured into replicating these principles in fully abiotic solid-state nanochannels (SSNs). Since the gating mechanisms of SSNs rely on variations in the physicochemical properties of the channel surface, the modification of their internal architecture and chemistry constitutes a powerful strategy to control the transport properties and, consequently, render specific functionalities. In this framework, both the design of the nanofluidic platform and the subsequent selection and attachment of different building blocks gain special attention. Similar to biological ion channels, functional SSNs offer the potential to finely modulate ion transport in response to various stimuli, leading to innovations in a variety of fields. This comprehensive review delves into the intricate world of ion transport across stimuli-responsive SSNs, focusing on the development of external voltage-controlled nanofluidic devices. This kind of field-effect nanofluidic technology has attracted special interest due to the possibility of real-time reconfiguration of the ion transport with a non-invasive strategy. These properties have found interesting applications in drug delivery, biosensing, and nanoelectronics. This document will address the fundamental principles of ion transport through SSNs and the construction, modification, and applications of external voltage-controlled SSNs. It will also address future challenges and prospects, offering a comprehensive perspective on this evolving field.

Large-area single-crystal TMD growth modulated by sapphire substrates.

Transition metal dichalcogenides (TMDs) have recently attracted extensive attention due to their unique physical and chemical properties; however, the preparation of large-area TMD single crystals is still a great challenge. Chemical vapor deposition (CVD) is an effective method to synthesize large-area and high-quality TMD films, in which sapphires as suitable substrates play a crucial role in anchoring the source material, promoting nucleation and modulating epitaxial growth. In this review, we provide an insightful overview of different epitaxial mechanisms and growth behaviors associated with the atomic structure of sapphire surfaces and the growth parameters. First, we summarize three epitaxial growth mechanisms of TMDs on sapphire substrates, namely, van der Waals epitaxy, step-guided epitaxy, and dual-coupling-guided epitaxy. Second, we introduce the effects of polishing, cutting, and annealing processing of the sapphire surface on the TMD growth. Finally, we discuss the influence of other growth parameters, such as temperature, pressure, carrier gas, and substrate position, on the growth kinetics of TMDs. This review might provide deep insights into the controllable growth of large-area single-crystal TMDs on sapphires, which will propel their practical applications in high-performance nanoelectronics and optoelectronics.

Lattice thermal conductivity and mechanical properties of the single-layer penta-NiN2 explored by a deep-learning interatomic potential.

Penta-NiN2, a novel pentagonal 2D sheet with potential nanoelectronic applications, is investigated in terms of its lattice thermal conductivity, stability, and mechanical behavior. A deep learning interatomic potential (DLP) is firstly generated from ab initio molecular dynamics (AIMD) data and then utilized for classical molecular dynamics simulations. The DLP's accuracy is verified, showing strong agreement with AIMD results. The dependence of thermal conductivity on size, temperature, and tensile strain, reveals important insights into the material's thermal properties. Additionally, the mechanical response of penta-NiN2 under uniaxial loading is examined, yielding a Young's modulus of approximately 368 GPa. The influence of vacancy defects on mechanical properties is analyzed, demonstrating a significant reduction in modulus, fracture stress, and ultimate strength. This study also investigates the influence of strain on phonon dispersion relations and phonon group velocity in penta-NiN2, shedding light on how alterations in the atomic lattice affect the phonon dynamics and, consequently, impact the thermal conductivity. This investigation showcases the ability of deep learning-based interatomic potentials in studying the properties of 2D penta-NiN2.

Fabrication and unraveling the morphological, structural, and dielectric features of PMMA-PEO-SiC–BaTiO3 promising quaternary nanocomposites for multifunctional nanoelectronics applications

Fabrication and unraveling the morphological, structural, and dielectric features of PMMA-PEO-SiC–BaTiO3 promising quaternary nanocomposites for multifunctional nanoelectronics applications

Giant supermagnonic Bloch point velocities in cylindrical ferromagnetic nanowires.

Achieving high velocities of magnetic domain walls is a crucial factor for their use as information carriers in modern nanoelectronic applications. In nanomagnetism and spintronics, these velocities are often limited either by internal domain wall instabilities, known as the Walker breakdown phenomenon, or by spin wave emission, known as the magnonic regime. In the rigid domain wall model, the maximum magnon velocity acts as an effective "speed of light", providing a relativistic analogy for the domain wall speed limitation. Cylindrical magnetic nanowires are an example of systems without the Walker breakdown phenomenon. Here we demonstrate that the magnonic limit could be outstandingly surpassed in cylindrical nanowires with high magnetization, such as iron. Our numerical modeling shows the Bloch point domain wall velocities as high as 14 km s-1, well above the magnonic limit estimated in the interval 1.7-2.0 km s-1. The key ingredient is the three-dimensional conical shape of the domain wall, which elongates and breaks during the dynamics, expelling backwards pairs of Bloch points. This leads to domain wall acceleration, the effect, which resembles the "jet propulsion". This effect will be very important for three-dimensional networks based on cylindrical magnetic nanowires.

Multipiezo Effect in Altermagnetic V2SeTeO Monolayer.

Strain engineering has been used as an efficient method to modulate various properties of quantum materials and electronic devices. One may establish piezo effects based on a disciplined response to the strain in multifunctional nanosystems. Inspired by a recent theoretical proposal on the interesting piezomagnetism and C-paired valley polarization in the V2Se2O monolayer, we predict a stable altermagnetic Janus monolayer V2SeTeO using density functional theory calculations. It exhibits a novel "multipiezo" effect combining piezoelectricity, piezovalley, and piezomagnetism. Most interestingly, the valley polarization and the net magnetization under strain in V2SeTeO exceed these in V2Se2O, along with the additional large piezoelectric coefficient. The "multipiezo" effect makes Janus monolayer V2SeTeO as a tantalizing material for potential applications in nanoelectronics, optoelectronics, spintronics, and valleytronics.

Stepwise Growth of Crystalline MoS2 in Atomic Layer Deposition

Transition metal dichalcogenides (TMDCs) are layered materials in which each layer is weakly bound by van der Waals forces. TMDCs have interesting intrinsic properties, including high mobility and excellent electrostatic controllability, even at monolayer thickness. Hence, they have emerged as promising materials for widespread applications in nanoelectronics, optoelectronics, gas sensors, etc. The aforementioned properties of TMDCs are significantly affected by the structuralquality and crystallinity. Accordingly, scalable techniques have been sought for synthesizing well-crystallized TMDCs.Atomic layer deposition (ALD) is considered a promising growth technique for transition metal dichalcogenides (TMDCs) because it ensures uniformity and homogeneity of the TMDC grains. However, the poor crystallinity of ALD-grown TMDCs remains a critical challenge. Although crystallinity depends on the growth mechanism, the growth behavior of crystalline TMDCs in ALD is unclear. We investigated the growth behavior of highly crystallized molybdenum disulfide (MoS2) by ALD at 650 oC with an extra pulse of remote H2 plasma. Growth at high temperatures using the activated species aided surface diffusion of the adsorbates. The ALD process facilitates repeated growth and saturation of MoS2, unlike the normal ALD of 3D bulk materials, where the film thickness monotonically increases with the number of ALD cycles. This unique behavior resulted from the evolution of the basal plane without dangling bonds. On the basal plane, MoS2 lateral growth dominates vertical growth, and prolonged incubation is required for nucleation on the basal plane. The grain size is small (up to two monolayers) because of the limited mobility on SiO2, and the grains of the third layer grow to a few hundred nanometers. These findings provide insights into the development of ALD technology for application to high-quality TMDCs.

High-Transconductance and Low-Leakage Current Single Aluminum Nitride Nanowire Field Effect Transistor

This study presents electrical transport properties of a catalyst-free grown single aluminum nitride nanowire field effect transistor (AlNNW-FET) exhibiting a very high transconductance of 26.9 pS, high on/off current ratio of 795.9, high conductivity of 9.8 x 10-4 Ω-1.cm-1, and a very low leakage current of 10 pA. The conductivity of AlN nanowire is two orders of magnitude higher than the reported studies. The AlNNW-FET reveals a dominant p-type conductivity. The p-type conductivity can be attributed to aluminum vacancies and complexes composed of Al vacancies and oxygen impurities. In consequence, the fabricated AlNNW-FET with high-performance, cost-effectiveness, and high-power efficiency is very well suited for use in low power and high temperature nanoelectronic and piezoelectric sensor applications, as well as integrated electro-optical devices including optomechanical devices and pyroelectric photodetectors.

Surface Reaction Kinetics for Inherent Selective Atomic Layer Deposition of Tantalum Oxide

The chemical principal and mechanisms that enable selective atomic layer depositions are gaining rapid growing interests, which have unlocked attractive avenues for the development of novel nanostructures by depositing atoms at desired surface locations. It has found versatile applications in emerging fields beyond semiconductor industry. Yet with the continuing downscaling, it is important to expand approaches for selective ALD with atomic scale precision on nanoscale features. The self-driven selective growth is needed, modifying specific surface down to atoms, to enable unprecedented capability of tuning the structure-property relationship for emerging applications. In this talk, the inherently selective atomic layer deposition processes will be discussed. Previously, we have demonstrated facet-selective ALD processes, which based on intrinsic differences of precursors chemisorption on terraces or step edges of nanoparticles. To expand the inherently ASD, the acidity and alkaline, surface electronegativity, lattice strains could be exploited to achieve this inhibitor-free selective deposition process. Tantalum oxide was studied on a series of oxide substrates. Although the oxides have -OH groups on the surface and proposed to have similar nucleation sites, there are long nucleation delays on basic oxides. The H-transfer reaction is a key factor to influence the reaction barrier. It is hard to nucleate on basic substrates because the H-transfer reaction is blocked. Another demonstration is the redox-coupled inherently selective ALD for self-alignment of tantalum oxide on SiO2/Cu nanopatterns. By adding an in-situ ethanol reduction pulse before each traditional binary ALD cycle, and the ‘reduction-adsorption-oxidation’ ALD process increases the selectivity. Self-aligned manufacturing on nanoscale Cu/SiO2 patterns without excessive mushroom growth at the edge and undesired nucleation defects on the Cu region. The process can be reliably repeated to yield more than 5 nm-thick Ta2O5 on the SiO2 region, while no undesired deposition occurs on Cu patterns. In addition, an anisotropic growth model with the dynamical competition of expansion and dissociation of the nucleus is proposed to nucleation delay are quantitively predicted and the model provides a practical method to evaluate the selectivity of ALD theoretically. It provides a new strategy for inherently selective ALD, which will expand the selective toolbox of nanofabrication for next-generation nanoelectronic applications.

Germanium Nanowires (GeNW): Synthesis, Structural Properties, and Electrical Characterization for Advanced Nanoelectronic Devices

The exponential progress of nanoelectronic devices necessitates the development of novel materials and production methodologies to fulfill the escalating demands for enhanced performance. This research aims to answer the current need for high-performance materials by proposing a revolutionary approach known as Germanium Nanowires for Advanced Nanoelectronic Devices (GeNW-ANED). GeNW-ANED achieves the integration of GeNW growth with advanced nanoelectronic applications. The system has several distinctive attributes, such as meticulous regulation of nanowire fabrication, adjustable electrical characteristics, and improved thermal qualities. The GeNW-ANED method exhibits exceptional performance across multiple experimental metrics, encompassing Electrical Conductivity (1.70 S/cm), Carrier Mobility (1685.83 cm²/Vs), Dielectric Constant (4.73), Specific Capacity (325.00 mAh/g), Growth Rate (5.93 nm/s), and Thermal Conductivity (3.47 W/mK). The impressive results achieved by GeNW-ANED establish it as a prospective contender for advanced nanoelectronic devices, offering the potential for improved performance and increased adaptability. The presented approach exhibits promise in influencing the trajectory of nanoelectronics, as it provides a sturdy basis for advancing the creation of forthcoming devices that possess enhanced electrical, thermal, and energy storage properties.

Theoretical study on the structural, electronic, mechanical, vibrational, thermodynamical, and optical properties of the two-dimensional PbC nanomaterials

Two-dimensional structures have attracted attention for application in nanoelectronics and optical devices; then, in this work, we are reporting the predicted physical properties (from first-principles calculations) for the two-dimensional PbC systems. Those physical properties reveal that the PbC monolayers (M-PbCs) in crystallographic planes (111) and (100); moreover, the PbC2 structures (paramagnetic and anisotropic compounds) are thermodynamical, structural, and mechanically stable but energetically and dynamically unstable at T = 0 K. However, the PbC2 non-magnetic (NM) is the most stable system at high temperatures. The M-PbCs exhibit sp 2 hybridization while the PbC2 NM shows sp 3 d 2 hybridization, forming a hexagonal lattice; meanwhile, the strong interaction at the C’s double bond in the PbC2 ferro and antiferromagnetic configurations (MAG) generates a rectangular lattice. These systems are ductile materials; however, the PbC2 (with metallic bonds) is more ductile than the M-PbCs due to the pronounced participation of the Pb 6p-orbitals. The M-PbCs have associated greater values for the hardness (than those for the PbC2 systems), but at high temperatures, the PbC2 MAG exhibits the highest mechanical resistance. The calculated optical data show that the M-PbCs and the PbC2 NM are promising as refractory materials. At the same time, the PbC2 MAG could be helpful in optical and optoelectronic devices capable of operating in the low frequencies of the UV region and in the infrared and visible regions.

Polymer nanocomposites comprising PVA matrix and Ag–BaTiO3 nanofillers: a comparative study of structural, dielectric and optical characteristics for optics and quantum nanoelectronic applications

Polymer nanocomposites comprising PVA matrix and Ag–BaTiO3 nanofillers: a comparative study of structural, dielectric and optical characteristics for optics and quantum nanoelectronic applications

Two-dimensional MSi2N4 (M = Ge, Sn, and Pb) monolayers: promising new materials for optoelectronic applications

The recent growth of two-dimensional (2D) layered crystals of MoSi2N4 and WSi2N4 has sparked significant interest due to their outstanding properties and potential applications. This development has paved the way for a new and large family of 2D materials with a general formula of MA 2 Z 4. In this regard, motivated by this exciting family, we propose two structural phases (1T- and 1H-) of MSi2N4 (M = Ge, Sn, and Pb) monolayers and investigate their structural, vibrational, mechanical, electronic and optical properties by using first-principles methods. The two phases have similar cohesive energies, while the 1T structures are found to be more energetically favorable than their 1H counterparts. The analysis of phonon spectra and ab initio molecular dynamics simulations indicate that all the suggested monolayers, except for 1H-GeSi2N4, are dynamically and thermally stable even at elevated temperatures. The elastic stability and mechanical properties of the proposed crystals are examined by calculating their elastic constants (C ij ), in-plane stiffness (), Poisson’s ratio (ν), and ultimate tensile strain (UTS). Remarkably, the considered systems exhibit prominent mechanical features such as substantial in-plane stiffness and high UTS. The calculated electronic band structures reveal that both the 1T- and 1H-MSi2N4 nanosheets are wide-band-gap semiconductors and their energy band gaps span from visible to ultraviolet region of the optical spectrum, suitable for high-performance nanoelectronic device applications. Lastly, the analysis of optical properties shows that the designed systems have isotropic optical spectra, and depending on the type of the system, robust absorption of ultraviolet and visible light (particularly in 1H-PbSi2N4 monolayer) is predicted. Our study not only introduces new members to the family of 2D MA 2 Z 4 crystals but also unveils their intriguing physical properties and suggests them as promising candidates for diverse nanomechanical and optoelectronic applications.

Bandgap design of fabricated BN/ZnO/Al2O3/TiO2 doped graphene using XPS approach

This study investigates the use of BN/ZnO/Al2O3/TiO2 nanoparticles as dopants for Graphene nanoparticles. The sintering process was employed to manufacture semiconductor materials. The bandgap serves as the central feature of an atomic heterojunction, playing a crucial role in determining the characteristics or overall quality of the semiconductor materials involved. X-ray photoelectron spectroscopy (XPS) was employed to ascertain the bandgap values of Boron (B), Nitrogen (N), and Carbon (C) at the interfaces of BN/Graphene, BN/ZnO/Graphene, BN/Al2O3/Graphene, and BN/TiO2/Graphene. The survey spectra were examined to provide evidence of atoms' presence and their respective atomic proportions. The analysis of the narrow spectra of XPS was employed to determine the binding energy of atoms within various materials. The conduction band offset (CBO) and valence band offset (VBO) of the aforementioned heterojunctions were computed. The estimation of the ratio between the conduction band offset (CBO) and the valence band offset (VBO), is denoted as ΔEc/ΔEv,. The significant change in the energy gap in the valance band concerning the change in conduction band energy demonstrates that this material possesses the characteristics of an exemplary semiconductor. The present investigation reveals that the BN/TiO2/Graphene heterojunction exhibits the highest values of ΔEv/ΔEc, namely 13.07 for nitrogen (N) and 15.07 for boron (B). The results suggest that the combination of BN/TiO2/Graphene semiconductors holds promising potential for applications in nanoelectronics.

Nanoelectronics Using Metal-Insulator Transition.

Metal-insulator transition (MIT) coupled with an ultrafast, significant, and reversible resistive change in Mott insulators has attracted tremendous interest for investigation into next-generation electronic and optoelectronic devices, as well as a fundamental understanding of condensed matter systems. Although the mechanism of MIT in Mott insulators is still controversial, great efforts have been made to understand and modulate MIT behavior for various electronic and optoelectronic applications. In this review, recent progress in the field of nanoelectronics utilizing MIT is highlighted. A brief introduction to the physics of MIT and its underlying mechanisms is begun. After discussing the MIT behaviors of various Mott insulators, recent advances in the design and fabrication of nanoelectronics devices based on MIT, including memories, gas sensors, photodetectors, logic circuits, and artificial neural networks are described. Finally, an outlook on the development and future applications of nanoelectronics utilizing MIT is provided. This review can serve as an overview and a comprehensive understanding of the design of MIT-based nanoelectronics for future electronic and optoelectronic devices.