Magnetic Phase Transition in Strained Two-Dimensional CrSeTe Monolayer

Tunable magnetic phase transition in two-dimensional materials is a fascinating subject of research.We perform first-principle calculations based on density functional theory to clarify the magnetic property of CrSeTe monolayer modulated by the biaxial compressive strain.Based on the stable structure confirmed by the phonon calculation,CrSeTe is determined to be a ferromagnetic metal that undergoes a phase transition from a ferromagnetic state to an antiferromagnetic state with nearly 2.75%compressive strain.We identify the stress-magnetism behavior originating from the changes in interactions between the nearest-neighboring Cr atoms(J_(1)) and the next-nearest-neighboring Cr atoms(J_(2)).Through Monte Carlo simulation,we find that the Curie temperature of the CrSeTe monolayer is 160 K.The CrSeTe monolayer could be an intriguing platform for the two-dimensional systems and potential spintronic material.

Synthesis and Luminescence Properties of(Y, Gd)(P, V)O_4:Eu^(3+), Bi^(3+) Red Nano-phosphors with Enhanced Photoluminescence by Bi^(3+), Gd^(3+) Doping

A series of(Y_(1-y), Gdy)_(0.95-x)(P_y, V_(1-y))O_4 :0.05Eu^(3+), xBi^(3+)+phosphors have been successfully prepared by a subsection method. The crystal structure, surface morphology and luminescence properties were investigated. It was found that the sintered samples crystallized in a tetragonal crystal system with space group I_(41)/amd(a = b = 0.7119 nm, c = 0.6290 nm). The products presented rod-like morphology with length of 100-150 nm and width of 50-100 nm. A maximum peak at 619 nm(~5D_0 →~7F_2) was observed in emission spectrum of the phosphors. It was also found that co-doping of Bi^(3+)+, P5+and Gd^(3+)ions into YVO_4:Eu^(3+)can not only made the right edge of the excitation band shift to the long-wavelength region, but also increased the emission intensity at 619 nm sharply and decreased the lifetime of fluorescence decay. These results may expand the application scope of the phosphors.

Quantum Transport across Amorphous-Crystalline Interfaces in Tunnel Oxide Passivated Contact Solar Cells: Direct versus Defect-Assisted Tunneling

Tunnel oxide passivated contact solar cells have evolved into one of the most promising silicon solar cell concepts of the past decade,achieving a record efficiency of 25%.We study the transport mechanisms of realistic tunnel oxide structures,as encountered in tunnel oxide passivating contact(TOPCon) solar cells.Tunneling transport is affected by various factors,including oxide layer thickness,hydrogen passivation,and oxygen vacancies.When the thickness of the tunnel oxide layer increases,a faster decline of conductivity is obtained computationally than that observed experimentally.Direct tunneling seems not to explain the transport characteristics of tunnel oxide contacts.Indeed,it can be shown that recombination of multiple oxygen defects in a-SiOx can generate atomic silicon nanowires in the tunnel layer.Accordingly,new and energetically favorable transmission channels are generated,which dramatically increase the total current,and could provide an explanation for our experimental results.Our work proves that hydrogenated silicon oxide(SiOx:H) facilitates high-quality passivation,and features good electrical conductivity,making it a promising hydrogenation material for TOPCon solar cells.By carefully selecting the experimental conditions for tuning the SiOx:H layer,we anticipate the simultaneous achievement of high open-circuit voltage and low contact resistance.

Network analysis of screening and regulation of differentially expressed genes in platelets of patients with myocardial infarction based on bioinformatics

Objective:To construct a core miRNA regulatory network in peripheral blood platelets of patients with acute myocardial infarction,,and to explore the role of peripheral blood platelet-related miRNAs in the occurrence and development of acute myocardial infarction.Methods:miRNA and mRNA expression profiling chips were used to screen out differentially expressed miRNA and mRNA.FunRich 3.1.3 software was performed to predict the transcription factors and target genes of differentially expressed miRNA,and then the predicted target genes were intersected with the differentially expressed genes screened by the gene chip.Cytoscape software was applied to construct miRNA-mRNA regulatory network,and we performed KEGG and GO analysis of genes in the regulatory network.Results:A total of 27 differentially expressed miRNAs and 2897 differentially expressed mRNAs were screened through gene expression profiling data.A total of 3563 target genes for differentially expressed miRNAs were predicted,and they were intersected with the differentially expressed mRNAs.After a one-to-one correspondence,there were 503 miRNA-mRNA regulatory relationships.KEGG enrichment and GO analysis of the target genes in the regulatory network showed that these target genes are mainly involved in PI3K-AKT signaling pathway,regulation of actin cytoskeleton,MAPK signaling pathway,human papillomavirus infection,and Ras signaling pathway.GO analysis indicated that the main molecular functions of genes from network included protein macromolecule adaptor activity,molecular adaptor activity,DNA binding transcription repressor activity,etc.Conclusion:We analyzed the miRNA-mRNA regulatory network and the different function in the platelets of acute myocardial infarction and non-infarction populations,and further understood the important role of platelets in the process of acute myocardial infarction,and deepened our understanding of the pathological mechanism of acute myocardial infarction.

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.

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.

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.