Silicon-based Electronic Devices Research Articles

A study on the effect of the geometric properties and surface defects on silicon chip flexibility for wearable electronics

A study on the effect of the geometric properties and surface defects on silicon chip flexibility for wearable electronics

Self-Assembled Monolayer Doping for MoTe2 Field-Effect Transistors: Overcoming PN Doping Challenges in Transition Metal Dichalcogenides.

Transition metal dichalcogenides (TMDs) have gained significant attention as next-generation semiconductor materials that could potentially overcome the integration limits of silicon-based electronic devices. However, a challenge in utilizing TMDs as semiconductors is the lack of an established PN doping method to effectively control their electrical properties, unlike those of silicon-based semiconductors. Conventional PN doping methods, such as ion implantation, can induce lattice damage in TMDs. Thus, chemical doping methods that can control the Schottky barrier while minimizing lattice damage are desirable. Here, we focus on the molybdenum ditelluride (2H-MoTe2), which has a hexagonal phase and exhibits ambipolar field-effect transistor (FET) properties due to its direct band gap of 1.1 eV, enabling concurrent transport of electrons and holes. We demonstrate the fabrication of p- or n-type unipolar FETs in ambipolar MoTe2 FETs using self-assembled monolayers (SAMs) as chemical dopants. Specifically, we employ 1H,1H,2H,2H perfluorooctyltriethoxysilane and (3-aminopropyl)triethoxysilane as SAMs for chemical doping. The selective SAMs effectively increase the hole and electron charge transport capabilities in MoTe2 FETs by 18.4- and 4.6-fold, respectively, due to the dipole effect of the SAMs. Furthermore, the Raman shift of MoTe2 by SAM coating confirms the successful p- and n-type doping. Finally, we demonstrate the fabrication of complementary inverters using SAMs-doped MoTe2 FETs, which exhibit clear full-swing capability compared to undoped complementary inverters.

Polysilyne chains bridged with beryllium lead to flat 2D Dirac materials

Polysilyne with repeating disilyne units, a silicon analogue of polyacetylene, has a high potential for application to various novel silicon-based electronic devices because of the unique properties of Si=Si units with a smaller HOMO–LUMO energy gap than that of C=C units. However, one-dimensional (1D) polysilyne has not been synthesized yet. Here we propose a planar and air-stable two-dimensional (2D) silicon-based material with one-atom thickness consisting of beryllium-bridged 1D all-trans polysilyne, based on the first-principles calculations. The flat structure of 1D polysilyne, which is essential for the air stability of silicon π-electron conjugated systems, is realized by embedding polysilyne in a planar sheet. It was found that the 2D crystal optimized at the rhombus unit cell with the D2h group symmetry is a silicon-based Dirac semimetal with linear dispersion at the Fermi energy and hosts anisotropic Dirac fermions.

Van der Waals-Interface-Dominated All-2D Electronics.

The interface is the device. As the feature size rapidly shrinks, silicon-based electronic devices are facing multiple challenges of material performance decrease and interface quality degradation. Ultrathin 2D materials are considered as potential candidates in future electronics by their atomically flat surfaces and excellent immunity to short-channel effects. Moreover, due to naturally terminated surfaces and weak van der Waals (vdW) interactions between layers, 2D materials can be freely stacked without the lattice matching limit to form high-quality heterostructure interfaces with arbitrary components and twist angles. Controlled interlayer band alignment and optimized interfacial carrier behavior allow all-2D electronics based on 2D vdW interfaces to exhibit more comprehensive functionality and better performance. Especially, achieving the same computing capacity of multiple conventional devices with small footprint all-2D devices is considered to be the key development direction of future electronics. Herein, the unique properties of all-2D vdW interfaces and their construction methods are systematically reviewed and the main performance contributions of different vdW interfaces in 2D electronics are summarized, respectively. Finally, the recent progress and challenges for all-2D vdW electronics are discussed, and how to improve the compatibility of 2D material devices with silicon-based industrial technology is pointed out as a critical challenge.

The comparison of a thin-film ZnO nanodevice with silicon-based electronic devices for diagnostic X-ray beam detection

Radiation detector devices are of fundamental importance for diagnosing diseases and helping to choose the most appropriate medical treatment. Zinc oxide (ZnO) thin films are not usually applied as X-ray photon sensors; however, this study intends to present potential results that enable its application for medical diagnostic use. The damage of the ionizing radiation in typical electronic components (such as transistors) occurs due to the defects generated either in the semiconductor crystal or in the insulating oxide layer, which compromises their long-term use as X-ray detectors. This study also provides some comparisons between the proposed ZnO nanodevice and other semiconductor devices, including photodiode, phototransistor, bipolar junction transistor (BJT), and MOSFET. Based on these comparisons, some advantages and disadvantages of using ZnO thin film will be discussed. Basically, it can be summarized that, although the other semiconductor devices produced a higher intense response, the innovative ZnO thin film-based device presented interesting results that make it promising for radiation detection applications. Furthermore, it has advantages such as superior physical resistance and radiation hardness when compared to ionization chambers and transistor-type devices, respectively.

Efficacy of Ion Implantation in Zinc Oxide for Optoelectronic Applications: A Review

Unlike the majority of the silicon-based electronic devices, optoelectronic devices are predominantly made using III–V and II–VI semiconductor compounds and their alloys because of their direct bandgap. Among these, zinc oxide (ZnO) is a multifunctional wide bandgap II–VI semiconductor material that has distinctive properties, such as large excitonic binding energy, high-sensitivity, nontoxicity, and good compatibility, which favors it to be considered for various optoelectronic applications including photoelectrochemical (PEC) water splitting, light-emitting diodes (LEDs), photovoltaics, and photodetectors. Though the research concentrated on ZnO started many decades ago, the renewed interest is rekindled only with the availability of high-quality single-crystal substrates, easy growth techniques of various nanostructures, and reports on p-type ZnO. Therefore, ZnO is being treated as a concentrated research focus during the last two decades by researchers encompassing a vast field starting from luminescent materials, energy storage and conversion, to biomedical sensors, and so on. Ion beam irradiation is a fruitful approach to modify the properties of semiconducting oxides by introducing not only impurities but also defects, strains, structural transitions, and others. The necessity of a timely in-depth and critical review of the progress on ion implantation in ZnO is the origin of this Review, which focuses on the recent implantation efforts in nanostructured ZnO thin films as well as single crystals. In the beginning, with an introduction to the general principles of ion implantation, this Review presents interactions and distribution of implantation-induced defects in ZnO. Next, comprehensive analyses on the influence of ion implantation on the optical, electrical properties, and optoelectronic applications including PEC water splitting and LEDs have been revealed. Most importantly, in each section from a “state-of-the-art” of the domain, some critical connections have been provided between the results of the theoretical simulations of the implanted ion-induced defects and the reported data, which in particular would be able to offer significant insights for both theoretical and experimental research community working with the oxide semiconductors. At the end, a summary with future directions for utilizing ion implantation for achieving ZnO thin-film-based high-performance devices has been presented. By including a sufficient breadth and depth of literature coverage in this Review, we believe that it would also tend to reveal the inconsistencies in the extant body of research.

Analysis of the generation mechanism of the S-shaped J–V curves of MoS2/Si-based solar cells

Amorphous–microcrystalline MoS2 thin films are fabricated using the sol-gel method to produce MoS2/Si-based solar cells. The generation mechanisms of the S-shaped current density–voltage (J–V) curves of the solar cells are analyzed. To improve the performance of the solar cells and address the problem of the S-shaped J–V curve, a MoS2 film and a p+ layer are introduced into the front and back interfaces of the solar cell, respectively, which leads to the formation of a p–n junction between the p-Si and the MoS2 film as well as ohmic contacts between the MoS2 film and the ITO, improving the S-shaped J–V curve. As a result of the high doping characteristics and the high work function of the p+ layer, a high–low junction is formed between the p+ and p layers along with ohmic contacts between the p+ layer and the Ag electrode. Consequently, the S-shaped J–V curve is eliminated, and a significantly higher current density is achieved at a high voltage. The device exhibits ideal p–n junction rectification characteristics and achieves a high power-conversion efficiency (CE) of 7.55%. The findings of this study may improve the application of MoS2 thin films in silicon-based solar cells, which are expected to be widely used in various silicon-based electronic and optical devices.

Calibrations coefficients for determination of concentrations of vacancy-oxygen-related complexes and oxygen dimer in silicon by means of infrared absorption spectroscopy

Vacancy-oxygen complexes VnOm (n, m ≥ 1) in crystalline silicon are nucleation centers for oxygen precipitates, which are widely used as internal getters in modern technologies of production of silicon-based electronic devices and integrated circuits. For the controllable formation of oxygen precipitates in Si crystals in the technology processes the methods of determination of concentrations of the VnOm complexes are required. The aim of the present work was to find values of the calibration coefficients for determination of concentrations of the VnOm defects in Si from intensities of infrared (IR) absorption bands associated with the local vibrational modes (LVM) of these complexes. A combined electrical (Hall effect) and optical (IR absorption) study of vacancy-oxygen defects in identical silicon crystals irradiated with 6 MeV electrons was carried out. Based on the analysis of the data obtained, the values of the calibration coefficient for the determination of concentration of the vacancy-oxygen (VO) complex in silicon by the infrared absorption method were established: for measurements at room temperature (RT) – NVO = 8.5 · 1016 · αVO-RT cm–3, in the case of low-temperature (LT, Т ≡ 10 K) measurements – NVO = 3.5 · 1016 · αVO-LT cm–3, where αVO-RT(LT) are absorption coefficients in maxima of the LVM bands due to the VO complex in the spectra measured at corresponding temperatures. Calibration coefficients for the determination of concentrations of other VnOm (VO2, VO3, VO4, V2O and V3O) complexes and the oxygen dimer (O2) from an analysis of infrared absorption spectra measured at room temperature have been also determined.

Boosting Static and Dynamic Performance of Integrated Solid-State Diodes By Peripheral Integration of Nanostructured Porous Silicon

Over the past two decades, different nanomaterials have been proposed for the design of novel silicon-based electronic devices or to push the performance of existing ones, leveraging the unique properties of charge carriers traveling in meso-to-nano scale structures.Porous silicon (PSi) is the nano- (n-PSi) to micro- (m-Psi) structured form of silicon achieved by anodic etching of a silicon wafer in acidic HF-based electrolytes. However, the low mobility and reduced lifetime of charge carriers traveling in n-PSi have been mainly perceived such as a deterioration the bulk silicon properties, thus hampering the use of n-PSi in micro and nano electronics to date.Here, we show that the integration of n-PSi in specific regions of a solid-state diode significantly improves both static and dynamic electrical performance of the diode, with respect to the unmodified device. Specifically, leveraging the unique mobility and lifetime of charge carriers traveling in the n-PSi layer, we achieve a significant increase of the breakdown voltage (>2x) and reduction of the turn-off time (about 30%). This improvement is shown to be robust with respect to n-PSi preparation conditions and diode typologies. Two dimensional (2D) TCAD simulations further corroborate that the improvement of the electrical performance of n-PSi modified diodes is related to the strong mobility and lifetime reduction of carriers in the nanostructured porous silicon layer. Remarkably, no significant drawbacks are observed after the peripheral integration of n-PSi in solid-state diodes, thus confirming the beneficial effect of n-PSi when employed for the modification of micro and nano electronic devices.A. Paghi, L. M. Strambini, F. F. Toia, M. Sambi, M. Marchesi, R. Depetro, M. Morelli, G. Barillaro, Peripheral Nanostructured Porous Silicon Boosts Static and Dynamic Performance Of Integrated Electronic Devices, Advanced Electronic Materials 6, 2000615 (2020).

Cr cation-anchored carbon nanosheets: synthesis, paramagnetism and ferromagnetism

Since the successfully synthesis of monolayer graphene, carbon-based materials have attracted wide and extensive attentions from researches. Due to the excellent transport capacity and conductivity, they are promising to be applied in electronic devices, even substituting the silicon-based electronic devices, optoelectronics and spintronics. Nevertheless, due to the non magnetic feature, many efforts have been devoted to endow carbon materials magnetism to apply them in the spintronic devices fabrication. Herein, a strategy of Cr cation solely anchored on two-dimensional carbon nanosheets by Cr–N bonds is developed, which introduces magnetism in carbon nanosheets. By extended x-ray absorption fine structure characterization, Cr cations are demonstrated to be atomically dispersed with Cr–N3 coordination. And after Cr–N3 anchored, carbon nanosheets exhibit ferromagnetic features with paramagnetic background. The magnetization varies with Cr content and reaches the maximum (Cr: 2.0%, 0.86 emu g−1) under 3 T at 50 K. The x-ray magnetic circular dichroism and first-principle calculations indicate that the magnetism is caused by the Cr3+ component of the anchored Cr cations. This study sets a single cation anchoring carbon as a suitable candidate for future spintronics.

Simulation and fabrication of carbon nanotube–nanoparticle interconnected structures

Abstract. With the rapid development of nanotechnology, the size of a device reaches sub-nanometer scale. The larger resistivity of interconnect leads to serious overheating of integrated circuits. Silicon-based electronic devices have also reached the physical limits of their development. The use of carbon nanotubes instead of traditional wires has become a new solution for connecting nano-structures. Nanocluster particles serving as brazing material play an important role in stabilizing the connection of carbon nanotubes, which places higher demands for nanoscale manipulation techniques. In this paper, the dynamic processes under different operating scenarios were simulated and analyzed, including probe propulsion nanoparticle operation, probe pickup nanoparticle operation and probe pickup nanocluster particle operation. Then, the SEM (Scanning Electron Microscope) was used for nanoparticle manipulation experiments. The smallest unit of carbon nanotube wire was obtained by three-dimensional (3D) construction of a carbon nanotube–silver nanocluster particle (CN-AgNP), which verified the feasibility of 3D manipulation of carbon nanotube wire construction. The experiments on the construction of carbon nanotube–nanocluster particle structures in three-dimensional operation were completed, and the smallest unit of carbon nanotube wire was constructed. This nano-fabrication technology will provide an efficient and mature technical means in the field of nano-interconnection.

Polarization switching in Bi0.8La0.2FeO3 films with ferroelectric/semiconductor heterojunctions

Bi0.8La0.2FeO3 (BLFO) films are deposited directly on low-resistance Si (100) substrates by the pulsed laser deposition method. Compared with the typical hysteresis loops of ferroelectric films, those of the BLFO/Si samples, with almost horizontal upper and lower ends, severely shrink in the center part, and the coercive voltage is extremely small. A systematic analysis of the dielectric and ferroelectric characteristics reveals that a p–n junction forms between BLFO and Si, with oxygen vacancies accumulating near the interface. The polarization switching is accompanied by the change of the interface barrier and the migration of charged defects. This work provides a reference for the direct growth of ferroelectric films on silicon substrates and is of great significance for the development of the silicon-based electronic devices.

Structure of one-dimensional monolayer Si nanoribbons on Ag(111)

One-dimensional silicon nanoribbons (SiNRs) have the potential for application to future electronic devices because of their compatibility with current silicon-based electronic devices and their theoretical outstanding electronic properties, such as the size-dependent band gap. Here we grew SiNRs by the deposition of Si on a Ag(111) surface. We investigated SiNRs on the Ag(111) surface using a combination of scanning tunneling microscopy (STM), atomic force microscopy (AFM), and density functional theory (DFT) calculations. The atomic resolution STM and AFM images revealed that SiNRs have the same width and align along the equivalent orientations of Ag(111). The main body of SiNRs was found to be symmetric about the long axes of the ribbons, but the terminals of SiNRs break the symmetry. The DFT calculation results revealed a buckled single-layer structure of SiNRs, which is composed of Si hexagonal and tetragonal rings.

Application of Micro/Nanofabrication Techniques to On-Chip Molecular Electronics.

Molecular electronics is a promising subject to overcome the size limitation of silicon-based electronic devices. In the past decades, various micro/nanofabrication techniques have been developed for constructing molecular junctions, and a number of breakthroughs are made in the characterizations and applications of the single-molecule device. The history and progress are reviewed in this article, laying emphasis on the recent works on the combination of micro/nanofabrication techniques with other techniques such as electrochemical deposition and surface-enhanced Raman spectroscopy (SERS). Some prototypical single-molecule devices such as molecular transistors are presented. Finally, the challenges and prospects in the fabrication of single-molecule devices are discussed.

Anisotropic Transport Property of Antimonene MOSFETs.

As silicon-based electronic devices rapidly reach their scaling limits, novel two-dimensional (2D) semiconductors, such as graphene nanoribbon, transition metal dichalcogenides, and phosphorene, are becoming promising channel materials. Antimonene has been proved suitable for ultrascaled field-effect transistors (FETs) benefiting from its superior semiconducting properties. Considering that antimonene shows different effective mass from 0° (zigzag) to 30° (armchair), we have calculated the anisotropic transport property of monolayer (ML) antimonene metal-oxide-semiconductor FET (MOSFETs), including on-state current, subthreshold swing, effective mass, intrinsic delay time, and power dissipation. Encouragingly, 0° (zigzag) and 19.1° directions ML antimonene MOSFETs with 4 nm gate length and 1 nm underlap achieve the International Technology Roadmap for Semiconductors (ITRS) high-performance (HP) goal in 2028. The performance of ML antimonene MOSFETs still can fulfill the ITRS HP goal, when the spin-orbit coupling effect is considered. The magnitude of on-state currents in all calculations generally varies inversely with the effective mass. Therefore, we predict that other transmission directions with effective masses between 0.291 and 0.388 m0 can also achieve the ITRS HP goal, which enables antimonene to be a promising channel material.

Single Molecule-Based Electronic Devices: A Review

In the face of the fact that the development of traditional silicon-based electronic devices is increasingly limited, single molecule electronic device, which has been attracting more and more attention, is considered as one of the most hopeful candidates to realize the miniaturization of conventional electronic devices. In this paper, an overview of single molecule electronic devices is provided, including molecular electronic devices and electrode types. First, several molecular electronic devices are presented, including molecular diodes, molecular memories, molecular wires, molecular field effect transistors (FET) and molecular switches. Then the influence of different electrode types of the transport characteristics is introduced, showing that graphene is a promising electrode material for single molecule electronic devices. Moreover, other excellent characteristics of molecular devices are briefly introduced, such as potential thermoelectric effects, new thermally induced spin transport phenomena and negative differential resistance (NDR) behavior. Finally, the future challenges to the development of electronic devices based on single molecules are described.

2D In2 S3 Nanoflake Coupled with Graphene toward High-Sensitivity and Fast-Response Bulk-Silicon Schottky Photodetector.

Silicon-based electronic devices, especially graphene/Si photodetectors (Gr/Si PDs), have triggered tremendous attention due to their simple structure and flexible integration of the Schottky junction. However, due to the relatively poor light-matter interaction and mobility of silicon, these Gr/Si PDs typically suffer an inevitable compromise between photoresponsivity and response speed. Herein, a novel strategy for coupling 2D In2 S3 with Gr/Si PDs is demonstrated. The introduction of the double-heterojunction design not only strengthens the light absorption of graphene/Si but also combines the advantages of the photogating effect and photovoltaic effect, which suppresses the dark current, accelerates the separation of photogenerated carriers, and brings photoconductive gain. As a result, In2 S3 /graphene/Si devices present an ultrahigh photoresponsivity of 4.53 × 104 A W-1 and fast response speed less than 40 µs, simultaneously. These parameters are an order of magnitude higher than pristine Gr/Si PDs and among the best values compared with reported 2D materials/Si heterojunction PDs. Furthermore, the In2 S3 /graphene/Si PD expresses outstanding long-term stability, with negligible performance degradation even after 1 month in air or 1000 cycles of operation. These findings highlight a simple and novel strategy for constructing high-sensitivity and ultrafast Gr/Si PDs for further optoelectronic applications.

Silicon Carbide Material and Railway Electrical traction Innovation

With the development of new materials and new energy industries, power devices have also made great progress. Compared with traditional silicon-based power electronic devices, wide-band gap semiconductor devices based on silicon carbide which are considered to be an important alternative to silicon-based devices, have excellent properties such as high breakdown voltage, thermal conductivity, and electron saturation drift and radiation resistance. At the same time, power electronic devices are widely used in high-speed railway. The application of a new type of silicon carbide power device in electrical traction is discussed. The experiment of system characteristics shows that the power device made of silicon carbide can effectively reduce the power loss of the system, adapt to the bad working conditions, and make the equipment lightweight.

Conformational Transitions of Phase-Separated Binary Molecules Assisted by Surface Dehalogenation.

Molecular devices have become an emergent branch of nanoscience and technology beyond traditional silicon-based electronic devices. The properties of these devices are intimately related to the molecular conformation and packing. In this article, three different conformations of melamine molecules are observed on Au(111), and a transition from the lying-down to standing-up phase with long-range order is realized in melamine chains with the assistance of hexabromobenzene (HBB). We argue that it is the expanding of HBB domains from hexagonal to the dimer phase due to surface dehalogenation that facilitates the dehydrogenation of melamine to form a standing-up conformation. Similar transitions are also accomplished on the Ag(111) surface. Our results provide an effective way to achieve standing-up molecular arrays with long-range order on relatively less active metals. This may have significant implications in fabricating organic thin film transistors.

From MEAs to MOAs: The Next Generation of Bioelectronic Interfaces for Neuronal Cultures.

Since their introduction in the early 1970s, microelectrode arrays (MEAs) have been dominating the electrophysiology market thanks to their reliability, extreme robustness, and usability. Over the past 40years, silicon technology has also played a role in the advancement of the field, and CMOS-based in vitro and in vivo systems are now able to achieve unprecedented spatial resolutions, giving the possibility to unveil hidden behavior of cellular aggregates down to the subcellular level. However, both the MEAs and silicon-based electronic devices present unavoidable problems such as their expensiveness, the usual rigidity of the employed materials, and the need of an (usually bulky) external reference electrode. Possible interesting alternatives to these incredibly useful devices unexpectedly lie in the field of organic electronics, thanks to the fast-growing pace of improvement that this discipline has undergone in the last 10-15 years. In this chapter, a particular organic transistor called organic charge-modulated field-effect transistor (OCMFET) will be presented as a promising bio-electronic interface, and a complete description of its employment as a detector of cellular electrical activity and as an ultrasensitive pH sensor will be provided, together with the discussion about the possibility of using such a device as an innovative multisensing tool for both electrophysiology and (neuro)pharmacology.