Disclosed is a method for synthesizing single crystalline molybdenum disulfide via a hydrothermal process that minimizes or eliminates carbon byproducts. The method involves providing two components, including a source of molybdenum and a mineralizer solution, to an inert reaction vessel, heating one zone sufficiently to dissolve the source of molybdenum in the mineralizer solution, and heating a second zone to a lower temperature to allow thermal transport to drive the dissolved material to the second zone, and then precipitate MoS.sub.2 on a seed crystal.

Disclosed herein are a method of forming a transition metal dichalcogenide thin film and a method of manufacturing a device including the same. The method of forming a transition metal dichalcogenide thin film includes: providing a substrate in a reaction chamber; depositing a transition metal dichalcogenide thin film on the substrate using a sputtering process that uses a transition metal precursor and a chalcogen precursor and is performed at a first temperature; and injecting the chalcogen precursor in a gas state and heat-treating the transition metal dichalcogenide thin film at a second temperature that is higher than the first temperature. The substrate may include a sapphire substrate, a silicon oxide (SiO.sub.2) substrate, a nanocrystalline graphene substrate, or a molybdenum disulfide (MoS.sub.2) substrate.

A method for growing a transition metal dichalcogenide layer involves arranging a substrate having a first transition metal contained pad is arranged in a chemical vapor deposition chamber. A chalcogen contained precursor is arranged upstream of the substrate in the chemical vapor deposition chamber. The chemical vapor deposition chamber is heated for a period of time during which a transition metal dichalcogenides layer, containing transition metal from the first transition metal contained pad and chalcogen from the chalcogen contained precursor, is formed in an area adjacent to the first transition metal contained pad.

Systems and methods disclosed and contemplated herein relate to manufacturing thin film semiconductors. Resulting thin film semiconductors are particularly suited for applications such as flexible optoelectronics and photovoltaic devices. Broadly, methods and techniques disclosed herein include high-temperature deposition techniques combined with lift-off in aqueous environments. These methods and techniques can be utilized to incorporate thin film semiconductors into substrates that have limited temperature tolerances.

Disclosed herein are a method of forming a transition metal dichalcogenide thin film and a method of manufacturing a device including the same. The method of forming a transition metal dichalcogenide thin film includes: providing a substrate in a reaction chamber; depositing a transition metal dichalcogenide thin film on the substrate using a sputtering process that uses a transition metal precursor and a chalcogen precursor and is performed at a first temperature; and injecting the chalcogen precursor in a gas state and heat-treating the transition metal dichalcogenide thin film at a second temperature that is higher than the first temperature. The substrate may include a sapphire substrate, a silicon oxide (SiO.sub.2) substrate, a nanocrystalline graphene substrate, or a molybdenum disulfide (MoS.sub.2) substrate.

The present invention provides methods to sputter deposit films comprising alkali metal compounds. At least one target comprising one or more alkali metal compounds and at least one metallic component is sputtered to form one or more corresponding sputtered films. The at least one target has an atomic ratio of the alkali metal compound to the at least one metallic component in the range from 15:85 to 85:15. The sputtered film(s) incorporating such alkali metal compounds are incorporated into a precursor structure also comprising one or more chalcogenide precursor films. The precursor structure is heated in the presence of at least one chalcogen to form a chalcogenide semiconductor. The resultant chalcogenide semiconductor comprises up to 2 atomic percent of alkali metal content, wherein at least a major portion of the alkali metal content of the resultant chalcogenide semiconductor is derived from the sputtered film(s) incorporating the alkali metal compound(s). The chalcogenide semiconductors are useful in microelectronic devices, including solar cells.

An electrically conductive thin film including: a material including a compound represented by Chemical Formula 1 and having a layered crystal structure,
Me.sub.mA.sub.a  Chemical Formula 1
wherein Me is Al, Ga, In, Si, Ge, Sn, A is S, Se, Te, or a combination thereof, and m and a each are independently a number selected so that the compound of Chemical Formula 1 is neutral; and a dopant disposed in the compound of Chemical Formula 1, wherein the dopant is a metal dopant that is different from Me and has an oxidation state which is greater than an oxidation state of Me, a non-metal dopant having a greater number of valence electrons than a number of valence electrons of A in Chemical Formula 1, or a combination thereof, and wherein the compound of Chemical Formula 1 includes a chemical bond which includes a valence electron of an s orbital of Me.

An example heterostructure semiconductor for sensing a gas comprises a substrate made of nanosheets of a compound of a first metal, wherein the compound of the first metal is sensitive to the gas to be sensed; one or more 1-Dimensional (1D) components fabricated on a surface of the substrate, the 1D components comprising a compound of a second metal, wherein the compound of the second metal is selective to the gas to be sensed; and a 2-Dimensional (2D) layer formed on the surface of the substrate in portions excluding the 1D components, wherein the 2D layer comprises compounds of the first and second metal. Method of fabrication of the heterostructure semiconductor and a chemiresistive sensor made thereof are also disclosed.

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 substrate includes: a support substrate having a first main surface and a surface layer region which includes at least the first main surface and is formed of any one material selected from the group consisting of boron nitride, molybdenum disulfide, tungsten disulfide, niobium disulfide, and aluminum nitride; and a graphene film disposed on the first main surface and having an atomic arrangement oriented in relation to an atomic arrangement of the material forming the surface layer region. Accordingly, the substrate is provided that enables a high mobility to be stably ensured in an electronic device manufactured to include the graphene film forming an electrically conductive portion.