University of Science and Technology Beijing

About: University of Science and Technology Beijing is a education organization based out in Beijing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 41558 authors who have published 44473 publications receiving 623229 citations. The organization is also known as: Beijing Steel and Iron Institute.

Electrical contacts to monolayer black phosphorus: A first-principles investigation

Abstract: We report first-principles theoretical investigations of possible metal contacts to monolayer black phosphorus (BP). By analyzing lattice geometry, five metal surfaces are found to have minimal lattice mismatch with BP: Cu(111), Zn(0001), In(110), Ta(110), and Nb(110). Further studies indicate Ta and Nb bond strongly with monolayer BP causing substantial bond distortions, but the combined Ta-BP and Nb-BP form good metal surfaces to contact a second layer BP. By analyzing the geometry, bonding, electronic structure, charge transfer, potential, and band bending, it is concluded that Cu(111) is the best candidate to form excellent Ohmic contact to monolayer BP. The other four metal surfaces or combined surfaces also provide viable structures to form metal/BP contacts, but they have Schottky character. Finally, the band bending property in the current-in-plane (CIP) structure where metal/BP is connected to a freestanding monolayer BP, is investigated. By both work function estimates and direct calculations of the two-probe CIP structure, we find that the freestanding BP channel is $n$ type.

From Dual-Mode Triboelectric Nanogenerator to Smart Tactile Sensor: A Multiplexing Design

Abstract: Triboelectric nanogenerators (TENGs) can be applied for the next generation of artificial intelligent products, where skin-like tactile sensing advances the ability of robotics to feel and interpret environment. In this paper, a flexible and thin tactile sensor was developed on the basis of dual-mode TENGs. The effective transduction of touch and pressure stimulus into independent and interpretable electrical signals permits the instantaneous sensing of location and pressure with a plane resolution of 2 mm, a high-pressure-sensing sensitivity up to 28 mV·N–1, and a linear pressure detection ranging from 40 to 140 N. Interestingly, this self-powered dual-mode sensor can even interpret contact and hardness of objects by analyzing the shape of the current peak, which makes this low-cost TENG-based sensor promising for applications in touch screens, electronic skins, healthcare, and environmental survey.

Lead-free antiferroelectric niobates AgNbO3 and NaNbO3 for energy storage applications

Abstract: Antiferroelectric materials are attractive for energy storage applications and are becoming increasingly important for power electronics. Lead-free silver niobate (AgNbO3) and sodium niobate (NaNbO3) antiferroelectric ceramics have attracted intensive interest as promising candidates for environmentally friendly energy storage products. This review provides the fundamental background of antiferroelectricity with an introduction to the definition of antiferroelectricity, historical research evolution of antiferroelectric materials, and some advanced techniques for structural characterization. Meanwhile, recent progress on lead-free antiferroelectric ceramics, represented by AgNbO3 and NaNbO3, is highlighted in terms of their crystal structures, phase transitions and potential dielectric energy storage applications. Specifically, the origin of the enhanced energy storage performance is discussed from a scientific point of view. The modification approaches are then summarized for the development of new strategies to further improve the energy storage performance. This article concludes with a discussion of the remaining challenges and opportunities for further development of lead-free antiferroelectrics.

Native point defects in few-layer phosphorene

Abstract: Using hybrid density functional theory combined with a semiempirical van der Waals dispersion correction, we have investigated the structural and electronic properties of vacancies and self-interstitials in defective few-layer phosphorene. We find that both a vacancy and a self-interstitial defect are more stable in the outer layer than in the inner layer. The formation energy and transition energy of both a vacancy and a self-interstitial $P$ defect decrease with increasing film thickness, mainly due to the upward shift of the host valence band maximum in reference to the vacuum level. Consequently, both vacancies and self-interstitials could act as shallow acceptors, and this well explains the experimentally observed $p$-type conductivity in few-layer phosphorene. On the other hand, since these native point defects have moderate formation energies and are stable in negatively charged states, they could also serve as electron compensating centers in $n$-type few-layer phosphorene.