Schemes for Single Electron Transistor Based on Double Quantum Dot Islands Utilizing a Graphene Nanoscroll, Carbon Nanotube and Fullerene

The single electron transistor (SET) is a nanoscale switching device with a simple equivalent circuit. It can work very fast as it is based on the tunneling of single electrons. Its nanostructure contains a quantum dot island whose material impacts on the device operation. Carbon allotropes such as fullerene (C60), carbon nanotubes (CNTs) and graphene nanoscrolls (GNSs) can be utilized as the quantum dot island in SETs. In this study, multiple quantum dot islands such as GNS-CNT and GNS-C60 are utilized in SET devices. The currents of two counterpart devices are modeled and analyzed. The impacts of important parameters such as temperature and applied gate voltage on the current of two SETs are investigated using proposed mathematical models. Moreover, the impacts of CNT length, fullerene diameter, GNS length, and GNS spiral length and number of turns on the SET’s current are explored. Additionally, the Coulomb blockade ranges (CB) of the two SETs are compared. The results reveal that the GNS-CNT SET has a lower Coulomb blockade range and a higher current than the GNS-C60 SET. Their charge stability diagrams indicate that the GNS-CNT SET has smaller Coulomb diamond areas, zero-current regions, and zero-conductance regions than the GNS-C60 SET.

Detecting Air Pollutant Molecules Using Tube-Shaped Single Electron Transistor

An air pollution detector is proposed based on a tube-shaped single-electron transistor (SET) sensor. By monitoring the flow control component of the detector, each air pollutant molecule can be placed at the center of a SET nanopore and is treated as an island of the SET device in the same framework. Electron transport in the SET was incoherent, and the performances of the SET were sensitive at the single molecule level. Employing first-principles calculations, electronic features of an air pollutant molecule within a tube-shaped SET environment were found to be independent of the molecule rotational orientations with respect to axis of symmetry, unlike the electronic features in a conventional SET environment. Charge stability diagrams of the island molecules were demonstrated to be distinct for each molecule, and thus they can serve as electronic fingerprints for detection. Using the same setup, quantification of the air pollutant can be realized at room temperature as well. The results presented herein may help provide guidance for the identification and quantification of various types of air pollutants at the molecular level by treating the molecule as the island of the SET component in the proposed detector.

Advanced Carbon Materials Derived from Polybenzoxazines: A Review

This comprehensive review article summarizes the key properties and applications of advanced carbonaceous materials obtained from polybenzoxazines. Identification of several thermal degradation products that arose during carbonization allowed for several different mechanisms (both competitive ones and independent ones) of carbonization, while also confirming the thermal stability of benzoxazines. Electrochemical properties of polybenzoxazine-derived carbon materials were also examined, noting particularly high pseudocapacitance and charge stability that would make benzoxazines suitable as electrodes. Carbon materials from benzoxazines are also highly versatile and can be synthesized and prepared in a number of ways including as films, foams, nanofibers, nanospheres, and aerogels/xerogels, some of which provide unique properties. One example of the special properties is that materials can be porous not only as aerogels and xerogels, but as nanofibers with highly tailorable porosity, controlled through various preparation techniques including, but not limited to, the use of surfactants and silica nanoparticles. In addition to the high and tailorable porosity, benzoxazines have several properties that make them good for numerous applications of the carbonized forms, including electrodes, batteries, gas adsorbents, catalysts, shielding materials, and intumescent coatings, among others. Extreme thermal and electrical stability also allows benzoxazines to be used in harsher conditions, such as in aerospace applications.

An Operation Guide of Si-MOS Quantum Dots for Spin Qubits

In the last 20 years, silicon quantum dots have received considerable attention from academic and industrial communities for research on readout, manipulation, storage, near-neighbor and long-range coupling of spin qubits. In this paper, we introduce how to realize a single spin qubit from Si-MOS quantum dots. First, we introduce the structure of a typical Si-MOS quantum dot and the experimental setup. Then, we show the basic properties of the quantum dot, including charge stability diagram, orbital state, valley state, lever arm, electron temperature, tunneling rate and spin lifetime. After that, we introduce the two most commonly used methods for spin-to-charge conversion, i.e., Elzerman readout and Pauli spin blockade readout. Finally, we discuss the details of how to find the resonance frequency of spin qubits and show the result of coherent manipulation, i.e., Rabi oscillation. The above processes constitute an operation guide for helping the followers enter the field of spin qubits in Si-MOS quantum dots.

ANALYSIS OF THE POSSIBILITY OF USING BATTERIES OF THE LATEST TECHNOLOGIES ON SAMPLES OF ARMORED WEAPONS AND MILITARY EQUIPMENT

The subject matter of the article is mass and dimensional characteristics of batteries, their design, electrical, operational parameters and energy capabilities. The goal of the study is the possibility of using maintenance-free batteries on samples of armored weapons and military equipment. The tasks to be solved are: to analyze the existing technologies for the batteries production, their advantages and disadvantages given the peculiarities of the operation of military equipment and the main technical characteristics of the batteries; by statistical data processing to investigate the dependences of “starter” discharge modes and energy capabilities of the batteries manufactured by technologies of different generations; to investigate the possibilities of constructive implementation of power supply formation taking into account possible design changes in the engine starting system, ensuring the necessary charge stability and compensation for exceeding the cost of gel and Absorbed in Glass Mat (AGM) batteries in comparison with the cost of the type 12ST85 ones. General scientific and special methods of scientific knowledge are used. The following results were obtained: The existing technologies of battery production, their advantages and disadvantages have been analyzed taking into account the peculiarities of the operation of military equipment and the main technical characteristics of batteries. The dependences of the “starter” discharge modes and the energy capabilities of batteries made by different technologies generations have been studied. Possibilities of constructive realization of power supply formation taking into account available constructive changes in the engine electric start system, providing the necessary charge stability and compensation for excess cost of gel and AGM batteries compared to the cost of batteries type 12ST85 have been investigated. Conclusions. Using at the samples of armored vehicles and military equipment batteries made by modern technology does not require fundamental structural changes in the electrical equipment of the machine. To meet the requirements of the standards for voltage parameters in the on-board armored weapons and military equipment networks, it is necessary to install an appropriate voltage relay regulator. The issue of exceeding the cost of gel and AGM batteries compared to the cost of type 12CT-85 ones can be compensated by the absence of costs for operating materials, maintenance personnel as well as the long service life of gel or AGM batteries compared to conventional lead-acid ones.

Spray-coated electret materials with enhanced stability in a harsh environment for an MEMS energy harvesting device

The charge stability of electret materials can directly affect the performance of electret-based devices such as electrostatic energy harvesters. In this paper, a spray-coating method is developed to deposit an electret layer with enhanced charge stability. The long-term stability of a spray-coated electret is investigated for 500 days and shows more stable performance than a spin-coated layer. A second-order linear model that includes both the surface charge and space charge is proposed to analyze the charge decay process of electrets in harsh environments at a high temperature (120 °C) and high humidity (99% RH); this model provides better accuracy than the traditional deep-trap model. To further verify the stability of the spray-coated electret, an electrostatic energy harvester is designed and fabricated with MEMS (micro-electromechanical systems) technology. The electret material can work as both the bonding interface and electret layer during fabrication. A maximum output power of 11.72 μW is harvested from a vibrating source at an acceleration of 28.5 m/s2. When the energy harvester with the spray-coated electret is exposed to a harsh environment (100 °C and 98% RH), an adequate amount of power can still be harvested even after 34 h and 48 h, respectively.