Enhanced Performance of Field-Effect Transistors Based on Black Phosphorus Channels Reduced by Galvanic Corrosion of Al Overlayers

Effect of vacancy defects on transport in all-phosphorene nanoribbon devices from first principles

Defects in experimentally manufactured phosphorene nanoribbons (PNRs) occur unavoidably, affecting the functionality of PNR-based devices. In this work, we theoretically propose and investigate an all-PNR devices with single-vacancy (SV) defects and double-vacancy (DV) defects along the zigzag direction, accounting for both hydrogen passivation and non-passivation scenarios. We discovered that, in the case of hydrogen passivation, the DV defect can introduce in-gap states, whereas the SV defect can result in p-type doping. The unpassivated hydrogen nanoribbon exhibits an edge state with a considerable influence on the transport properties, which also masks the effect of defects on transport; furthermore, it demonstrates the phenomenon of negative differential resistance, whose occurrence and characteristics depend less on the presence or absence of defects.

Passively Q-switched Tm:YAP laser with a tantalum aluminum carbide saturable absorber

Tantalum aluminum carbide (Ta₄AlC₃) phase ceramic (MAX) material has attracted much attention because of its high conductivity, high strength, corrosion resistance, and good optical properties. However, there are too few reports on lasers with Ta₄AlC₃-based saturable absorbers (SAs). We prepared and characterized a Ta₄AlC₃-based SA whose nonlinear absorption performances were achieved at a 2 µm waveband range and which was used in a passively Q-switched (PQS) Tm:YAP laser. In the PQS mode, a maximum average output power of 0.78 W was achieved with the central output wavelength of 1991.86 nm from a PQS Tm:YAP laser, corresponding to a pulse duration of 926 ns at 143.8 kHz.

Electrode Potential Regulation of Carbon Fiber Based on Galvanic Coupling and Its Application in Electrochemical Grafting

The reaction behavior of carbon fiber in electrochemical grafting is related to its electrode potential. In this paper, carbon fiber and metals with different electrode potentials were used to form combined electrodes to regulate the electrode potential of carbon fiber. The results showed that galvanic coupling was formed in the combined anode when the potential difference between carbon fiber and the metal (Δϕ = ϕ_CF0 - ϕ_metal) was higher than 0.05 V. The electrode potential of carbon fiber was reduced due to cathodic polarization. The electrode potential of carbon fiber after galvanic coupling was proportional to the self-corrosion potential of metals. By applying the electrode potential regulation of carbon fiber in the electrochemical grafting of poly(glycidyl methacrylate) onto the carbon fiber surface, the grafting effect was significantly improved with the decrease of the electrode potential of carbon fibers. The grafting amount of carbon fibers increased from 0.83 to 69.86% as the electrode potential of carbon fibers dropped from 0.55 to -0.72 V. Consequently, the interfacial shear strength of the carbon fiber composite was remarkably promoted from 47.59 to 81.41 MPa, increasing by 71.07%.

Two-Dimensional Pnictogen for Field-Effect Transistors

Two-dimensional (2D) layered materials hold great promise for various future electronic and optoelectronic devices that traditional semiconductors cannot afford. 2D pnictogen, group-VA atomic sheet (including phosphorene, arsenene, antimonene, and bismuthene) is believed to be a competitive candidate for next-generation logic devices. This is due to their intriguing physical and chemical properties, such as tunable midrange bandgap and controllable stability. Since the first black phosphorus field-effect transistor (FET) demo in 2014, there has been abundant exciting research advancement on the fundamental properties, preparation methods, and related electronic applications of 2D pnictogen. Herein, we review the recent progress in both material and device aspects of 2D pnictogen FETs. This includes a brief survey on the crystal structure, electronic properties and synthesis, or growth experiments. With more device orientation, this review emphasizes experimental fabrication, performance enhancing approaches, and configuration engineering of 2D pnictogen FETs. At the end, this review outlines current challenges and prospects for 2D pnictogen FETs as a potential platform for novel nanoelectronics.

Recent progress in black phosphorus and black-phosphorus-analogue materials: properties, synthesis and applications

Black phosphorus (BP), a novel two-dimensional (2D) layered semiconductor material, has attracted tremendous attention since 2014 due to its prominent carrier mobility, thickness-dependent direct bandgap and in-plane anisotropic physical properties. BP has been considered as a promising material for many applications, such as in transistors, photonics, optoelectronics, sensors, batteries and catalysis. However, the development of BP was hampered by its instability under ambient conditions, as well as by the lack of methods to synthesize large-area and high quality 2D nanofilms. Recently, some BP-analogue materials such as binary phosphides (MPx), transition metal phosphorus trichalcogenides (MPX3), and 2D group V (pnictogens) and 2D group VI materials have attracted increasing interest for their unique and stable structures, and excellent physical and chemical properties. This article, which focuses on BP and BP-analogue materials, will present their crystal structure, properties, synthesis methods and applications. Also the similarity and difference between BP and BP-analogue materials will be discussed, and the presentation of the future opportunities and challenges of the materials are included at the end.

A Highly Effective π-π Stacking Strategy To Modify Black Phosphorus with Aromatic Molecules for Cancer Theranostics

Even though black phosphorus (BP) has exhibited outstanding capabilities in biomedical, physical, and energy fields, the issues of degradation under ambient conditions and unreactive functional interface limit its further application. There are numerous methodologies utilized to prevent BP degradation; however, these methods usually generate further problems and normally do not involve alterations to the chemically inert BP. Herein, for the first time, we propose a simple and efficient strategy to prepare and modify BP nanosheets (p-BPNSs) by employing aromatic 1-pyrenylbutyric acid through a noncovalent π-π stacking interaction. This strategy not only adopts a novel strategy for enhancing the stability of BPNSs but also paves a convenient way to anchor other active biomolecules such as a targeting effect to extend the biomedical applications of BPNSs. The modified p-BPNSs exhibit enhanced physical and chemical stabilities as well as rich carboxyl groups for further modification. In this work, RGD-modified p-BPNSs exhibit targeted photothermal therapy ability against cancer in both in vitro and in vivo studies, owing to anchoring of arginine-glycine-aspartic acid (RGD) tripeptides, which could target nanosheets into the tumor site through systematic circulation. Consequently, this work not only provides a new concept for modifying and protecting the BP but also opens a novel window for extending the biomedical application of BP by surface engineering.