Structures for a bipolar junction transistor and methods of fabricating a structure for a bipolar junction transistor. The structure includes an emitter and a collector comprised of a first two-dimensional material having a first conductivity type, and an intrinsic base comprised of a second two-dimensional material having a second conductivity type different than the first conductivity type. The intrinsic base is laterally positioned between the emitter and the collector.

A semiconductor device includes a substrate, a semiconductor structure suspending over the substrate and comprising a source region, a drain region, and a channel region disposed between the source region and the drain region. The channel region includes a doped two-dimensional (2D) material layer comprising a first portion on an upper surface of the channel region. The semiconductor device also includes an interfacial layer surrounding the channel region including the first portion of the doped 2D material layer, and and a gate electrode surrounding the interfacial layer.

Disclosed are a semiconductor device and a manufacturing method therefor. The semiconductor device includes a semiconductor substrate, an epitaxial layer grown on a side of the semiconductor substrate; a quantum dot transport layer disposed on the epitaxial layer; and a gate oxide layer disposed on the quantum dot transport layer. With this arrangement, the semiconductor device provided by the present disclosure may reduce a threshold voltage while ensuring gate electrode reliability.

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 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.

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.

A film forming method of forming a metal oxide film on a substrate in a processing container, includes: supplying a raw material gas containing an organometallic precursor into the processing container; removing a residual gas remaining in the processing container after the supplying the raw material gas; subsequently, supplying an oxidizing agent that oxidizes the raw material gas into the processing container; removing a residual gas remaining in the processing container after the supplying the oxidizing agent; and supplying a hydrogen-containing reducing gas into the processing container, simultaneously with the supplying the raw material gas or sequentially after the supplying the raw material gas.

A method of manufacturing a semiconductor device includes forming a three-dimensional (3D) structure on a substrate, forming an adsorption control layer to cover an upper portion of the 3D structure, and forming a material layer on the adsorption control layer and on a lower portion of the 3D structure that is not covered by the adsorption control layer, wherein a minimum thickness of the material layer on the adsorption control layer is less than a maximum thickness of the material layer on the lower portion of the 3D structure.

Embodiments described herein include a method for forming a vertical hetero-stack and a device including a vertical hetero-stack. An example method is used to form a vertical hetero-stack of a first nanostructure and a second nanostructure arranged on an upper surface of the first nanostructure. The first nanostructure is formed by a first transition metal dichalcogenide, TMDC, material and the second nanostructure is formed by a second TMDC material. The example method includes providing the first nanostructure on a substrate. The method also includes forming a reactive layer of molecules on the first nanostructure along a periphery of the upper surface. The method further includes forming the second nanostructure by a vapor deposition process. The second TMDC material nucleates on the reactive layer of molecules along the periphery and grows laterally therefrom to form the second nanostructure on the upper surface.

A method of forming a Group II-VI multijunction semiconductor device comprises providing a Group IV substrate, forming a first subcell from a first Group II-VI semiconductor material, forming a second subcell from a second Group II-VI semiconductor material, and removing the substrate. The first subcell is formed over the substrate and has a first bandgap, while the second subcell is formed over the first subcell and has a second bandgap which is smaller than the first bandgap. Additional subcells may be formed over the second subcell with the bandgap of each subcell smaller than that of the preceding subcell and with each subcell preferably separated from the preceding subcell by a tunnel junction. Prior to the removal of the substrate, a support layer is affixed to the last-formed subcell in opposition to the substrate.