A method for making a transition metal dichalcogenide crystal having a chemical formula represented as MX.sub.2 is provided, wherein M represents a central transition metal element, and X represents a chalcogen element. The method includes providing a MX.sub.2 polycrystalline powder, a MX.sub.2 seed crystal, and a transport medium. The MX.sub.2 polycrystalline powder and the transport medium are placed in a first reaction chamber. The first reaction chamber and the MX.sub.2 seed crystal are placed in a second reaction chamber having a source end and a deposition end opposite to the source end. The first reaction chamber is placed at the source end, and the MX.sub.2 seed crystal is placed at the deposition end.

A method for making a transition metal dichalcogenide crystal having a chemical formula represented as MX.sub.2 is provided, wherein M represents a central transition metal element, and X represents a chalcogen element. The method includes providing a MX.sub.2 polycrystalline powder, a MX.sub.2 seed crystal, and a transport medium. The MX.sub.2 polycrystalline powder and the transport medium are placed in a first reaction chamber. The first reaction chamber and the MX.sub.2 seed crystal are placed in a second reaction chamber having a source end and a deposition end opposite to the source end. The first reaction chamber is placed at the source end, and the MX.sub.2 seed crystal is placed at the deposition end.

The present embodiments relate to a method for manufacturing a two-dimensional material using a top-down method, the method includes the steps of preparing a bulk crystal, forming a metal layer on the bulk crystal, and then attaching a thermal release tape on the metal layer, exfoliating a two-dimensional material to which the metal layer and the thermal release tape have been attached from the bulk crystal, transferring the two-dimensional material to which the metal layer and the thermal release tape have been attached onto a substrate, and removing the thermal release tape and the metal layer from the substrate onto which the two-dimensional material has been transferred.

The present embodiments relate to a method for manufacturing a two-dimensional material using a top-down method, the method includes the steps of preparing a bulk crystal, forming a metal layer on the bulk crystal, and then attaching a thermal release tape on the metal layer, exfoliating a two-dimensional material to which the metal layer and the thermal release tape have been attached from the bulk crystal, transferring the two-dimensional material to which the metal layer and the thermal release tape have been attached onto a substrate, and removing the thermal release tape and the metal layer from the substrate onto which the two-dimensional material has been transferred.

A semiconductor device includes first pillar-shaped semiconductor layers, a first gate insulating film formed around the first pillar-shaped semiconductor layers, gate electrodes formed of metal and formed around the first gate insulating film, gate lines formed of metal and connected to the gate electrodes, a second gate insulating film formed around upper portions of the first pillar-shaped semiconductor layers, first contacts formed of a first metal material and formed around the second gate insulating film, second contacts formed of a second metal material and connecting upper portions of the first contacts and upper portions of the first pillar-shaped semiconductor layers, diffusion layers formed in lower portions of the first pillar-shaped semiconductor layers, pillar-shaped insulator layers formed on the second contacts, variable-resistance films formed around upper portions of the pillar-shaped insulator layers, and lower electrodes formed around lower portions of the pillar-shaped insulator layers and connected to the variable-resistance films.

A semiconductor device includes first pillar-shaped semiconductor layers, a first gate insulating film formed around the first pillar-shaped semiconductor layers, gate electrodes formed of metal and formed around the first gate insulating film, gate lines formed of metal and connected to the gate electrodes, a second gate insulating film formed around upper portions of the first pillar-shaped semiconductor layers, first contacts formed of a first metal material and formed around the second gate insulating film, second contacts formed of a second metal material and connecting upper portions of the first contacts and upper portions of the first pillar-shaped semiconductor layers, diffusion layers formed in lower portions of the first pillar-shaped semiconductor layers, pillar-shaped insulator layers formed on the second contacts, variable-resistance films formed around upper portions of the pillar-shaped insulator layers, and lower electrodes formed around lower portions of the pillar-shaped insulator layers and connected to the variable-resistance films.

The present application discloses a nonlinear optical crystal material, preparation method and application of the nonlinear optical crystal material. The nonlinear optical crystal material has an excellent infrared nonlinear optical performance, whose frequency-doubling intensity can reach 9.3 times of AgGaS.sub.2 with the same particle size, and it meets type-I phase matching; and its laser damage threshold can reach 7.5 times of AgGaS.sub.2 with the same particle size. The nonlinear optical crystal material has important application value in the frequency-converters which can be used for frequency doubling, sum frequency, difference frequency, optical parametric oscillation of laser in mid and far infrared waveband, and the like.

The present application discloses a nonlinear optical crystal material, preparation method and application of the nonlinear optical crystal material. The nonlinear optical crystal material has an excellent infrared nonlinear optical performance, whose frequency-doubling intensity can reach 9.3 times of AgGaS.sub.2 with the same particle size, and it meets type-I phase matching; and its laser damage threshold can reach 7.5 times of AgGaS.sub.2 with the same particle size. The nonlinear optical crystal material has important application value in the frequency-converters which can be used for frequency doubling, sum frequency, difference frequency, optical parametric oscillation of laser in mid and far infrared waveband, and the like.

A conductive material including a first element selected from a transition metal, a platinum-group element, a rare earth element, and a combination thereof, a second element having an atomic radius which is 10 percent less than to 10 percent greater than an atomic radius of the first element, and a chalcogen element, wherein the conductive material has a layered crystal structure.

A conductive material including a first element selected from a transition metal, a platinum-group element, a rare earth element, and a combination thereof, a second element having an atomic radius which is 10 percent less than to 10 percent greater than an atomic radius of the first element, and a chalcogen element, wherein the conductive material has a layered crystal structure.