Improving Methods of Doping on Black Phosphorus

Black phosphorus (BP) is a 2D semiconducting material with high carrier mobility. It is usually p-type due to oxidation states near its valence band. Although achieved through other growth methods, n-type doping has not yet been accomplished through the modern chemical vapor transport (CVT) growth method. To address this issue, small amounts of tellurium were added to Red Phosphorus to act as a dopant during the CVT growth process in addition to tin(Sn) and tin(IV) iodide, which facilitate growth. The chemicals are heated up to 600°C and precisely cooled in a 21-hour process, during which BP crystals should form. After successful growth, the synthesized BP is used as a channel material in transistors. N-type transistor characterization will be investigated, which will indicate whether the BP has been doped successfully using the safer and faster CVT growth process

Computing Networks Enabled Semantic Communications

Semantic communication has shown great potential in boosting the effectiveness and reliability of communications. However, its systems to date are mostly enabled by deep learning, which requires demanding computing resources. This article proposes a framework for the computing networks enabled semantic communication system, aiming to offer sufficient computing resources for semantic processing and transmission. Key techniques including semantic sampling and reconstruction, semantic-channel coding, semantic-aware resource allocation and optimization are introduced based on the cloud-edge-end computing coordination. Two use cases are demonstrated to show advantages of the proposed framework. The article concludes with several future research directions

Light-activated ferroelectric transition in layer dependent Bi2O2Se films

Bi2O2Se has attracted intensive attention due to its potential in electronics, optoelectronics, as well as ferroelectric applications. Despite that, there have only been a handful of experimental studies based on ultrafast spectroscopy to elucidate the carrier dynamics in Bi2O2Se thin films, Different groups have reported various ultrafast timescales and associated mechanisms across films of different thicknesses. A comprehensive understanding in relation to thickness and fluence is still lacking. In this work, we have systematically explored the thickness-dependent Raman spectroscopy and ultrafast carrier dynamics in chemical vapor deposition (CVD)-grown Bi2O2Se thin films on mica substrate with thicknesses varying from 22.44 nm down to 4.62 nm at both low and high pump fluence regions. Combining the thickness dependence and fluence dependence of the slow decay time, we demonstrate a ferroelectric transition in the thinner (< 8 nm) Bi2O2Se films, influenced by substrate-induced compressive strain and non-equilibrium states. Moreover, this transition can be manifested under highly non-equilibrium states. Our results deepen the understanding of the interplay between the ferroelectric phase and semiconducting characteristics of Bi2O2Se thin films, providing a new route to manipulate the ferroelectric transition

A medium-entropy transition metal oxide cathode for high-capacity lithium metal batteries

The limited capacity of the positive electrode active material in non-aqueous rechargeable lithium-based batteries acts as a stumbling block for developing high-energy storage devices. Although lithium transition metal oxides are high-capacity electrochemical active materials, the structural instability at high cell voltages (e.g., >4.3 V) detrimentally affects the battery performance. Here, to circumvent this issue, we propose a Li1.46Ni0.32Mn1.2O4-x (0 < x < 4) material capable of forming a medium-entropy state spinel phase with partial cation disordering after initial delithiation. Via physicochemical measurements and theoretical calculations, we demonstrate the structural disorder in delithiated Li1.46Ni0.32Mn1.2O4-x, the direct shuttling of Li ions from octahedral sites to the spinel structure and the charge-compensation Mn3+/Mn4+ cationic redox mechanism after the initial delithiation. When tested in a coin cell configuration in combination with a Li metal anode and a LiPF6-based non-aqueous electrolyte, the Li1.46Ni0.32Mn1.2O4-x-based positive electrode enables a discharge capacity of 314.1 mA h g−1 at 100 mA g−1 with an average cell discharge voltage of about 3.2 V at 25 ± 5 °C, which results in a calculated initial specific energy of 999.3 Wh kg−1 (based on mass of positive electrode’s active material)

The Application Of Association Rule Mining To Remotely Sensed Data

The explosive growth in data and database has generated an urgent need for new techniques and tools that can intelligently and automatically transform the processed data into useful information and knowledge. Data mining is such a technique. In this paper, we consider the mining of association rules from remotely sensed data and its application in precision. Based on the characteristics of the remotely sensed data and the problem itself, we present a bit oriented formal model and discuss the issues of partitioning quantitative attributes into equal, unequal and discontinuous partitions. We propose two new pruning techniques and compare the performances with a base algorithm. An improvement in performance is shown when using these pruning techniques

Synergistic enhancement effect of polydopamine–polyethyleneimine hybrid films for a visible-light photoelectrochemical biosensing interface

Photoelectrochemical (PEC) active interfaces exhibiting visible-light responses and good electron-transfer capabilities are key to the development of PEC biosensors. In this study, bioinspired polydopamine (PDA)–polyethyleneimine (PEI) hybrid films were designed to engineer inorganic semiconductors and construct PEC biosensing interfaces. The charge-transfer capability and visible-light-response property of PDA were combined with the electron-attracting ability of PEI to produce a synergistic PEC-enhancement effect. The achieved PEC-enhancement effect was versatile for photoanode and photocathode semiconductors. Further, the role of PEI doping was revealed via electrochemical investigations. Compared with the PDA sensing platform, the hybrid sensing interface offered by the PDA–PEI film exhibited enhanced analytical performances toward ascorbic acid (AA), achieving a larger detection range and a lower limit of detection