The layer-dependent properties are still unclarified in two-dimensional(2D)vertical heterostructures.In this study,we layer-bylayer deposited semimetalβ-In2Se3 on monolayer MoS2 to form verticalβ-In2Se3/MoS2 heteros...The layer-dependent properties are still unclarified in two-dimensional(2D)vertical heterostructures.In this study,we layer-bylayer deposited semimetalβ-In2Se3 on monolayer MoS2 to form verticalβ-In2Se3/MoS2 heterostructures by chemical vapor deposition.The defect-mediated nucleation mechanism inducesβ-In2Se3 nanosheets to grow on monolayer MoS2,and the layer number of stackedβ-In2Se3 can be precisely regulated from 1 layer(L)to 13 L by prolonging the growth time.Theβ-In2Se3/MoS2 heterostructures reveal tunable type-Ⅱband alignment arrangement by altering the layer number ofβ-In2Se3,which optimizes the internal electron transfer.Meanwhile,the edge atomic structure ofβ-In2Se3 stacking on monolayer MoS2 shows the reconstruction derived from large lattice mismatch(~29%),and the presence ofβ-In2Se3 also further increases the electrical conductivity ofβ-In2Se3/MoS2 heterostructures.Attributed to abundant layer-dependent edge active sites,edge reconstruction,improved hydrophilicity,and high electrical conductivity ofβ-In2Se3/MoS2 heterostructures,the edge ofβ-In2Se3/MoS2 heterostructures exhibits excellent electrocatalytic hydrogen evolution performance.Lower onset potential and smaller Tafel slope can be observed at the edge of monolayer MoS2 coupled with 13-Lβ-In2Se3.Hence,the outstanding conductive layers coupled with edge reconstruction in 2D vertical heterostructures play decisive roles in the optimization of electron energy levels and improvement of layer-dependent catalytic performance.展开更多
We have investigated the electronic and structural properties of inorganic nanoribbons （BN, AIN, GaN, SiC, and ZnO） with unpassivated zigzag edges using density functional theory calculations. We find that, in gener...We have investigated the electronic and structural properties of inorganic nanoribbons （BN, AIN, GaN, SiC, and ZnO） with unpassivated zigzag edges using density functional theory calculations. We find that, in general, the unpassivated zigzag edges can lead to spin-splitting of energy bands. More interestingly, the inorganic nanoribbons A1N and SiC with either one or two edges unpassivated are predicted to be half metallic. Possible structural reconstruction at the unpassivated edges and its effect on the electronic properties are investigated. The unpassivated N edge in the BN nanoribbon and P edge in the AlP nanoribbon are energetically less stable than the corresponding reconstructed edge. Hence, edge reconstruction at the two edges may occur at high temperatures. Other unpassivated edges of the inorganic nanoribbons considered in this study are all robust against edge reconstruction.展开更多
基金The work was supported by the National Natural Science Foundation of China(Nos.22175060 and 21975067)Natural Science Foundation of Hunan Province of China(Nos.2021JJ10014 and 2021JJ30092)+1 种基金X.X.X thanks to the National Science Foundation of China(No.12104385)The computational resources were provided by the supercomputer TianHe in Changsha,China.
文摘The layer-dependent properties are still unclarified in two-dimensional(2D)vertical heterostructures.In this study,we layer-bylayer deposited semimetalβ-In2Se3 on monolayer MoS2 to form verticalβ-In2Se3/MoS2 heterostructures by chemical vapor deposition.The defect-mediated nucleation mechanism inducesβ-In2Se3 nanosheets to grow on monolayer MoS2,and the layer number of stackedβ-In2Se3 can be precisely regulated from 1 layer(L)to 13 L by prolonging the growth time.Theβ-In2Se3/MoS2 heterostructures reveal tunable type-Ⅱband alignment arrangement by altering the layer number ofβ-In2Se3,which optimizes the internal electron transfer.Meanwhile,the edge atomic structure ofβ-In2Se3 stacking on monolayer MoS2 shows the reconstruction derived from large lattice mismatch(~29%),and the presence ofβ-In2Se3 also further increases the electrical conductivity ofβ-In2Se3/MoS2 heterostructures.Attributed to abundant layer-dependent edge active sites,edge reconstruction,improved hydrophilicity,and high electrical conductivity ofβ-In2Se3/MoS2 heterostructures,the edge ofβ-In2Se3/MoS2 heterostructures exhibits excellent electrocatalytic hydrogen evolution performance.Lower onset potential and smaller Tafel slope can be observed at the edge of monolayer MoS2 coupled with 13-Lβ-In2Se3.Hence,the outstanding conductive layers coupled with edge reconstruction in 2D vertical heterostructures play decisive roles in the optimization of electron energy levels and improvement of layer-dependent catalytic performance.
文摘We have investigated the electronic and structural properties of inorganic nanoribbons （BN, AIN, GaN, SiC, and ZnO） with unpassivated zigzag edges using density functional theory calculations. We find that, in general, the unpassivated zigzag edges can lead to spin-splitting of energy bands. More interestingly, the inorganic nanoribbons A1N and SiC with either one or two edges unpassivated are predicted to be half metallic. Possible structural reconstruction at the unpassivated edges and its effect on the electronic properties are investigated. The unpassivated N edge in the BN nanoribbon and P edge in the AlP nanoribbon are energetically less stable than the corresponding reconstructed edge. Hence, edge reconstruction at the two edges may occur at high temperatures. Other unpassivated edges of the inorganic nanoribbons considered in this study are all robust against edge reconstruction.
