过渡金属二硫化物(Transition Metal Dichalcogenides,TMDs)以其优异的光电子学特性,在诸如光捕获、光电探测、光电晶体管、发光二极管以及纳米激光器等领域中展现出了强大的应用潜力,成为当前研究前沿热点之一.少层TMDs材料的带隙处于...过渡金属二硫化物(Transition Metal Dichalcogenides,TMDs)以其优异的光电子学特性,在诸如光捕获、光电探测、光电晶体管、发光二极管以及纳米激光器等领域中展现出了强大的应用潜力,成为当前研究前沿热点之一.少层TMDs材料的带隙处于可见和近红外区间,其激子在室温下具有很大的束缚能、高谐振子强度,且单层TMDs由于空间反演对称性的破缺具有能谷选择的圆二色性等,这些特性使得TMDs材料格外引人注目.金属纳米结构的表面等离激元具有亚波长的光局域特性,可通过合理的结构设计实现对其共振波长、频谱宽度、近场增强倍数、远场辐射特性的灵活控制.将等离激元光学结构和过渡金属二硫化物相结合可大幅拓宽纳米光子学前沿基础问题研究与纳米光电器件的设计应用.本文综述了表面等离激元和TMDs材料复合体系的最新研究进展,着重阐述了为何这类复合体系能够提供他们各自体系所不能具有的特性.比如,表面等离激元的近场增强(场局域)效应可极大增强许多纳米光学系统中的光与物质相互作用强度,可用于对TMDs材料的光吸收、光发射、光电流以及非线性光学等过程进行调制.TMDs材料具备的受外界环境调控的强激子效应和能谷选择的圆二色性等特性,可为表面等离激元纳米结构提供丰富的主动调制手段与能谷自由度.最后展望了该新型复合体系未来的研究方向和机遇.展开更多
二维过渡金属二硫化物(transition metal dichalcogenides,TMDCs)因其原子级平坦的表面、可调的能带结构等优势而在光学、电学、热学等领域受到广泛关注,并且为解决传统硅基晶体管尺寸进一步微缩面临的挑战提供了新的机遇.能带工程是调...二维过渡金属二硫化物(transition metal dichalcogenides,TMDCs)因其原子级平坦的表面、可调的能带结构等优势而在光学、电学、热学等领域受到广泛关注,并且为解决传统硅基晶体管尺寸进一步微缩面临的挑战提供了新的机遇.能带工程是调控二维TMDCs材料电子结构并研究其物理学特性的重要手段.本文从本征调控和外部调控两个方面综述了近年来二维TMDCs材料中的能带调控策略,主要包括本征层数调控、零维点缺陷调控(晶格空位构筑、掺杂/合金化)、施加应变、构筑异质结等.在现有研究成果的基础上,对未来的研究方向进行了展望.展开更多
Two-dimensional materials(2D)with unique physicochemical properties have been widely studied for their use in many applications,including as hydrogen evolution catalysts to improve the efficiency of water splitting.Re...Two-dimensional materials(2D)with unique physicochemical properties have been widely studied for their use in many applications,including as hydrogen evolution catalysts to improve the efficiency of water splitting.Recently,typical 2D materials MoS2,graphene,MXenes,and black phosphorus have been widely investigated for their application in the hydrogen evolution reaction(HER).In this review,we summarize three efficient strategies—defect engineering,heterostructure formation,and heteroatom doping—for improving the HER performance of 2D catalysts.The d-band theory,density of states,and Fermi energy level are discussed to provide guidance for the design and construction of novel 2D materials.The challenges and prospects of 2D materials in the HER are also considered.展开更多
Low-dimensional materials have excellent properties which are closely related to their dimensionality.However,the growth mechanism underlying tunable dimensionality from 2D triangles to 1D ribbons of such materials is...Low-dimensional materials have excellent properties which are closely related to their dimensionality.However,the growth mechanism underlying tunable dimensionality from 2D triangles to 1D ribbons of such materials is still unrevealed.Here,we establish a general kinetic Monte Carlo model for transition metal dichalcogenides(TMDs) growth to address such an issue.Our model is able to reproduce several key findings in experiments,and reveals that the dimensionality is determined by the lattice mismatch and the interaction strength between TMDs and the substrate.We predict that the dimensionality can be well tuned by the interaction strength and the geometry of the substrate.Our work deepens the understanding of tunable dimensionality of low-dimensional materials and may inspire new concepts for the design of such materials with expected dimensionality.展开更多
本团队通过基于密度泛函理论的第一性原理方法,系统地研究了HfSe2/PtSe2范德瓦尔斯异质结(van der Waals heterostructures,vdWHs)的电子性质,包括堆垛方式、层间耦合、应变和外电场的影响.发现堆垛方式可以调节能带对齐类型--AA,AB′...本团队通过基于密度泛函理论的第一性原理方法,系统地研究了HfSe2/PtSe2范德瓦尔斯异质结(van der Waals heterostructures,vdWHs)的电子性质,包括堆垛方式、层间耦合、应变和外电场的影响.发现堆垛方式可以调节能带对齐类型--AA,AB′和AC′堆垛时为Ⅱ型,AB,AC,AA′则为Ⅰ型.在六种堆垛方式中,AA堆垛是最稳定的,其层间距为2.87A,带隙为1.0 eV,Ⅱ型的能带对齐方式有利于电子-空穴载流子的分离.进一步的计算表明,HfSe_(2)/PtSe_(2)异质结的电子性质可以通过垂直应变和双轴面内应变有效调节:在施加应变或改变层间距后,可以在HfSe_(2)/PtSe_(2)异质结中观察到从Ⅱ型到Ⅰ型能带对齐类型的转变;不仅如此,压缩应变和层间耦合还可以有效调控异质结的带隙大小.本研究将为未来HfSe_(2)/PtSe_(2)异质结在纳米电子及光电设备中的应用提供理论基础.展开更多
文摘过渡金属二硫化物(Transition Metal Dichalcogenides,TMDs)以其优异的光电子学特性,在诸如光捕获、光电探测、光电晶体管、发光二极管以及纳米激光器等领域中展现出了强大的应用潜力,成为当前研究前沿热点之一.少层TMDs材料的带隙处于可见和近红外区间,其激子在室温下具有很大的束缚能、高谐振子强度,且单层TMDs由于空间反演对称性的破缺具有能谷选择的圆二色性等,这些特性使得TMDs材料格外引人注目.金属纳米结构的表面等离激元具有亚波长的光局域特性,可通过合理的结构设计实现对其共振波长、频谱宽度、近场增强倍数、远场辐射特性的灵活控制.将等离激元光学结构和过渡金属二硫化物相结合可大幅拓宽纳米光子学前沿基础问题研究与纳米光电器件的设计应用.本文综述了表面等离激元和TMDs材料复合体系的最新研究进展,着重阐述了为何这类复合体系能够提供他们各自体系所不能具有的特性.比如,表面等离激元的近场增强(场局域)效应可极大增强许多纳米光学系统中的光与物质相互作用强度,可用于对TMDs材料的光吸收、光发射、光电流以及非线性光学等过程进行调制.TMDs材料具备的受外界环境调控的强激子效应和能谷选择的圆二色性等特性,可为表面等离激元纳米结构提供丰富的主动调制手段与能谷自由度.最后展望了该新型复合体系未来的研究方向和机遇.
文摘二维过渡金属二硫化物(transition metal dichalcogenides,TMDCs)因其原子级平坦的表面、可调的能带结构等优势而在光学、电学、热学等领域受到广泛关注,并且为解决传统硅基晶体管尺寸进一步微缩面临的挑战提供了新的机遇.能带工程是调控二维TMDCs材料电子结构并研究其物理学特性的重要手段.本文从本征调控和外部调控两个方面综述了近年来二维TMDCs材料中的能带调控策略,主要包括本征层数调控、零维点缺陷调控(晶格空位构筑、掺杂/合金化)、施加应变、构筑异质结等.在现有研究成果的基础上,对未来的研究方向进行了展望.
文摘Two-dimensional materials(2D)with unique physicochemical properties have been widely studied for their use in many applications,including as hydrogen evolution catalysts to improve the efficiency of water splitting.Recently,typical 2D materials MoS2,graphene,MXenes,and black phosphorus have been widely investigated for their application in the hydrogen evolution reaction(HER).In this review,we summarize three efficient strategies—defect engineering,heterostructure formation,and heteroatom doping—for improving the HER performance of 2D catalysts.The d-band theory,density of states,and Fermi energy level are discussed to provide guidance for the design and construction of novel 2D materials.The challenges and prospects of 2D materials in the HER are also considered.
基金supported by the Ministry of Science and Technology (No.2018YFA0208702)the National Natural Science Foundation of China (No.32090044,No. 21973085,No.21833007,No.21790350)+1 种基金Anhui Initiative in Quantum Information Technologies (AHY 090200)the Fundamental Research Funds for the Central Universities (WK2340000104)。
文摘Low-dimensional materials have excellent properties which are closely related to their dimensionality.However,the growth mechanism underlying tunable dimensionality from 2D triangles to 1D ribbons of such materials is still unrevealed.Here,we establish a general kinetic Monte Carlo model for transition metal dichalcogenides(TMDs) growth to address such an issue.Our model is able to reproduce several key findings in experiments,and reveals that the dimensionality is determined by the lattice mismatch and the interaction strength between TMDs and the substrate.We predict that the dimensionality can be well tuned by the interaction strength and the geometry of the substrate.Our work deepens the understanding of tunable dimensionality of low-dimensional materials and may inspire new concepts for the design of such materials with expected dimensionality.
文摘本团队通过基于密度泛函理论的第一性原理方法,系统地研究了HfSe2/PtSe2范德瓦尔斯异质结(van der Waals heterostructures,vdWHs)的电子性质,包括堆垛方式、层间耦合、应变和外电场的影响.发现堆垛方式可以调节能带对齐类型--AA,AB′和AC′堆垛时为Ⅱ型,AB,AC,AA′则为Ⅰ型.在六种堆垛方式中,AA堆垛是最稳定的,其层间距为2.87A,带隙为1.0 eV,Ⅱ型的能带对齐方式有利于电子-空穴载流子的分离.进一步的计算表明,HfSe_(2)/PtSe_(2)异质结的电子性质可以通过垂直应变和双轴面内应变有效调节:在施加应变或改变层间距后,可以在HfSe_(2)/PtSe_(2)异质结中观察到从Ⅱ型到Ⅰ型能带对齐类型的转变;不仅如此,压缩应变和层间耦合还可以有效调控异质结的带隙大小.本研究将为未来HfSe_(2)/PtSe_(2)异质结在纳米电子及光电设备中的应用提供理论基础.
