Study of Shifted UV Emission Peak of ZnO Nanowire Arrays

We have obtained vertically aligned ZnO nanowire arrays synthesized by microwave-assisted heating method with different growth time.From the room-temperature PL measurement,the strong deep-level emission and weak near band edge(NBE)emission can be seen.The deep-level emissions became weaker and deep-level emissions became stronger when the samples were annealed at 300℃for 30 min,meanwhile,the NBE emission peaks get red-shifted with growth time,and the longer the growth time,the more the peak shifting.This phenomenon can be attributed that the diameter of ZnO nanowires increases with growth time.This PL emission phenomenon is important in research of optoelectronic application.

Ferroelectric polarization effect on the photocatalytic activity of Bi_(0.9)Ca_(0.1)FeO_(3)/CdS S-scheme nanocomposites

BiFeO_(3)(BFO),as a kind of narrow band-gap semiconductor material,has gradually emerged advantages in the application of photocatalysis.In this paper,Ca doped BFO nanoparticles Bi_(0.9)Ca_(0.1)FeO_(3)(BCFO)were prepared by sol-gel method.And BCFO and CdS nanocomposites with two morphologies were obtained by controlling the time of loading CdS under a low temperature liquid phase process.It is found that the band gap becomes narrower after doping Ca into BFO,which is conducive to the absorption of visible light.Among all the samples,the composite of CdS nanowires and BCFO nanoparticles obtained by reaction time of 10 min has the best photocatalytic performance.The degradation rate of Methyl Orange solutionwas 94%after 90min under visible light irradiation,whichwasmuch higher than that of pure BCFO and CdS.Furthermore,significant enhancement in the degradation rate(100%degradation in 60 min)can be achieved in poled samples after electric polarization process.The highest degradation rate is due to the promoted separation of photogenerated carriers induced by the internal polarization field and the formation of S-scheme heterostructure between BCFO and CdS.Such BCFO-CdS nanocomposites may bring new insights into designing highly efficient photocatalyst.

A novel contact engineering method for transistors based on two-dimensional materials

Contact engineering is of critical importance for two-dimensional(2D)transition metal dichalcogenide(TMD)-based devices.However,there are only a few solutions to overcome this obstacle because of the complexity of the TMD-contact interface.In this work,we propose a novel method using a soft plasma treatment followed by the seamless deposition of a metal electrode to reduce the contact resistance of MoS_(2)field effect transistors(FETs).The treated FETs exhibit three times higher mobility than the control FETs without plasma treatment.The soft plasma treatment can remove the facial sulfur atoms and expose the middle Mo atoms so that they come into direct contact with the metal electrode,thus greatly improving the contact behavior.First-principles calculation is also performed to support the experimental results.Our potentially scalable strategy can be extended to the whole family of TMD based FETs to provide a possible route of device processsing technology for 2D device application.

MBenes:Two-dimensional transition-metal borides with ordered metal vacancies

2D MBenes have been theoretically predicted to possess unique electronic structures and physicochemical properties,and thus shown great promise in various applications.However,the synthesis of individual single-layer MBene remains a grand challenge due to its orthorhombic structure of MAB phases.Recently,scientists from Link?ping University have fabricated 2D monolayer Mo4/3B2-xTzwith ordered metal vacancies.Their results demonstrated the feasibility of top-down approach by chemical exfoliation of laminated compounds and provided the principle for further preparation of a wealth of MBenes.

Temperature-and field angular-dependent helical spin period characterized by magnetic dynamics in a chiral helimagnet MnNb_(3)S_(6)

The chiral magnets with topological spin textures provide a rare platform to explore topology and magnetism for potential application implementation.Here,we study the magnetic dynamics of several spin configurations on the monoaxial chiral magnetic crystal MnNb_(3)S_(6)via broadband ferromagnetic resonance(FMR)technique at cryogenic temperature.In the high-field forced ferromagnetic state(FFM)regime,the obtained frequency f vs.resonance field H_(res) dispersion curve follows the wellknown Kittel formula for a single FFM,while in the low-field chiral magnetic soliton lattice(CSL)regime,the dependence of H_(res) on magnetic field angle can be well-described by our modified Kittel formula including the mixture of a helical spin segment and the FFM phase.Furthermore,compared with the sophisticated Lorentz micrograph technique,the observed magnetic dynamics corresponding to different spin configurations allow us to obtain temperature-and field-dependent proportion of helical spin texture and helical spin period ratio L(H)/L(0)via our modified Kittel formula.Our results demonstrated that fieldand temperature-dependent nontrivial magnetic structures and corresponding distinct spin dynamics in chiral magnets can be an alternative and efficient approach to uncovering and controlling nontrivial topological magnetic dynamics.

Van der Waals layered ferroelectrie CuInP_(2)S_(6):Physical properties and device applications

Copper indium thiophosphate,CuInP_(2)S_(6),has attracted much attention in recent years due to its van der Waals layered structure and robust ferroelectricity at room temperature.In this review,we aim to give an overview of the various properties of CuInP_(2)S_(6),covering structural,ferroelectric,dielectric,piezoelectric and transport properties,as well as its potential applications.We also highlight the remaining questions and possible research directions related to this fascinating material and other compounds of the same family.