A method of making an atomic layer nanoribbon that includes forming a double atomic layer ribbon having a first monolayer and a second monolayer on a surface of the first monolayer, wherein the first monolayer and the second monolayer each contains a transition metal dichalcogenide material, oxidizing at least a portion of the first monolayer to provide an oxidized portion, and removing the oxidized portion to provide an atomic layer nanoribbon of the transition metal dichalcogenide material. Also provided are double atomic layer ribbons, double atomic layer nanoribbons, and single atomic layer nanoribbons prepared according to the method.

Processes for forming Mo and W containing thin films, such as MoS.sub.2, WS.sub.2, MoSe.sub.2, and WSe.sub.2 thin films are provided. Methods are also provided for synthesizing Mo or W beta-diketonate precursors. Additionally, methods are provided for forming 2D materials containing Mo or W.

A photodetector based on PtSe.sub.2 and a silicon nanopillar array includes a PMMA light-transmitting protective layer, a graphene transparent top electrode, a silicon nanopillar array structure coated with few-layer PtSe.sub.2, and metal electrodes of the graphene transparent top electrode and the silicon nanopillar array structure. A method for preparing the photodetector includes steps of: preparing graphene with a CVD method; preparing a silicon nanopillar array structure through dry etching; coating few-layer PtSe.sub.2 on surfaces of the silicon nano-pillar array structure through laser interference enhanced induction CVD; preparing graphene transparent top electrode; and magnetron-sputtering metal electrodes. The photodetector prepared by the present invention has a detection range from visible light to near-infrared wavebands. The silicon nanopillar array structure enhances light absorption of the detector, so that the detector has high sensitivity, simple structure and strong practicability.

A method to form a 2-Dimensional transistor channel may include depositing an amorphous layer comprising a 2-dimensional material, implanting an implant species into the amorphous layer; and annealing the amorphous layer after the implanting. As such, the amorphous layer may form a doped crystalline layer.

Disclosed are a transition metal chalcogenide thin-layer material, a preparation method and an application thereof. The preparation method comprises: uniformly spreading a transition metal source between two substrates to prepare a sandwich structure; performing a heat treatment on the sandwich structure to fuse and bond the two substrates together, and performing a chemical vapor deposition reaction on a chalcogen element source and the fused and bonded sandwich structure under the protection of a protective gas, wherein the transition metal source is heated to dissolve and diffuse at a reaction temperature, separated out from surfaces of the substrates, and reacts with the chalcogen element source. The prepared thin-layer material is uniformly distributed in a centimeter-level substrate.

A method for manufacturing a transition metal-dichalcogenide thin film is provided. The method for manufacturing a transition metal-dichalcogenide thin film can comprise the steps of: preparing a base substrate within a chamber; preparing a precursor comprising a transition metal; repeatedly carrying out, multiple times, a step of providing the precursor on the base substrate and a step of purging the chamber, thereby forming, on the base substrate, a preliminary thin film in which the precursor is adsorbed; and manufacturing a transition metal-dichalcogenide thin film by heat treating the preliminary thin film in a gas atmosphere comprising a chalcogen element.

By widening a terrace on a crystal surface on a bottom face of a recess by step flow caused by heating, a flat face is formed on the bottom face of the recess, a two-dimensional material layer made of a two-dimensional material is formed on the formed flat face, and then a device made of the two-dimensional material layer is produced.

A method of making an atomic layer nanoribbon that includes forming a double atomic layer ribbon having a first monolayer and a second monolayer on a surface of the first monolayer, wherein the first monolayer and the second monolayer each contains a transition metal dichalcogenide material, oxidizing at least a portion of the first monolayer to provide an oxidized portion, and removing the oxidized portion to provide an atomic layer nanoribbon of the transition metal dichalcogenide material. Also provided are double atomic layer ribbons, double atomic layer nanoribbons, and single atomic layer nanoribbons prepared according to the method.

Disclosed is a method of fabricating a Janus transition metal dichalcogenide thin film. More particularly, the method includes a first step of depositing a transition metal dichalcogenide thin film including a first chalcogen element on an oxide silicon substrate; a second step of a vacancy forming in the transition metal dichalcogenide thin film; and a third step of substituting the first chalcogen element with a second chalcogen element to form a Janus transition metal dichalcogenide thin film. The first step, the second step, and the third step may be performed in a single CVD process in a same reaction chamber.

Therefore, the present disclosure can shorten the processing time of a Janus transition metal dichalcogenide thin film and can reduce the manufacturing cost thereof. In addition, the present disclosure can minimize damage to the Janus transition metal dichalcogenide thin film during the fabrication process, thereby being capable of a high-quality single-crystal Janus transition metal dichalcogenide thin film.

Vapor deposition methods for depositing transition metal dichalcogenide (TMDC) films, such as rhenium sulfide thin films, are provided. In some embodiments TMDC thin films are deposited using a deposition cycle in which a substrate in a reaction space is alternately and sequentially contacted with a vapor phase transition metal precursor, such as a transition metal halide, a reactant comprising a reducing agent, such as NH.sub.3 and a chalcogenide precursor. In some embodiments rhenium sulfide thin films are deposited using a vapor phase rhenium halide precursor, a reducing agent and a sulfur precursor. The deposited TMDC films can be etched by chemical vapor etching using an oxidant such as O.sub.2 as the etching reactant and an inert gas such as N.sub.2 to remove excess etching reactant. The TMDC thin films may find use, for example, as 2D materials.