A process for preparing stacks of metal chalcogenide flakes includes: (a) reacting together a source of the metal atom of the target metal chalcogenide with a source of the chalcogenide atom of the target metal chalcogenide, in the presence of a spacer, so as to produce flakes of the metal chalcogenide; (b) depositing metal chalcogenide flakes obtained using step (a) onto a substrate to form a stack of assembled metal chalcogenide flakes, wherein the spacer contains an alkyl chain linked to a functional group able to bond to the metal chalcogenide surface, said alkyl chain having a length of less than 18 carbon atoms, preferably between 6 and 14 carbon atoms.

A semiconductor nanocrystal particle including a transition metal chalcogenide represented by Chemical Formula 1, the semiconductor nanocrystal particle having a size of less than or equal to about 100 nanometers, and a method of producing the same:
M.sup.1M.sup.2Cha.sub.3  Chemical Formula 1 wherein M.sup.1 is Ca, Sr, Ba, or a combination thereof, M.sup.2 is Ti, Zr, Hf, or a combination thereof, and Cha is S, Se, Te, or a combination thereof.

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.

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.

The invention relates to a vertical compound semiconductor structure having a substrate with a first main surface and an opposite second main surface, a vertical channel opening extending completely through the substrate between the first main surface and the second main surface and a layer stack arranged within the vertical channel opening. The layer stack includes an electrically conductive layer arranged within the vertical channel opening and a compound semiconductor layer arranged within the vertical channel opening. The compound semiconductor layer includes a compound semiconductor layer arranged on the electrically conductive layer and connected galvanically to the electrically conductive layer. Further, the invention relates to a method for producing such a vertical compound semiconductor structure.

Transition metal dichalcogenide films and methods for depositing transition metal dichalcogenide films on a substrate are described. Methods for converting transition metal oxide films to transition metal dichalcogenide films are also described. The substrate is exposed to a metal precursor and an oxidant to form a transition metal oxide film; the transition metal oxide film is exposed to a chalcogenide precursor to form the transition metal dichalcogenide film.

The present disclosure describes a method that includes forming a first two-dimensional (2D) layer on a first substrate and attaching a second 2D layer to a carrier film. The method also includes bonding the second 2D layer to the first 2D layer to form a heterostack including the first and second 2D layers. The method further includes separating the first 2D layer of the heterostack from the first substrate and attaching the heterostack to a second substrate. The method further includes removing the carrier film from the second 2D layer.

Provided is a field effect transistor including a gate insulating layer having a two-dimensional material. The field effect transistor may include a first channel layer; a second channel layer disposed on the first channel layer; a gate insulating layer disposed on the second channel layer; a gate electrode disposed on the gate insulating layer; a first electrode electrically connected to the first channel layer; and a second electrode electrically connected to the second channel layer. Here, the gate insulating layer may include an insulative, high-k, two-dimensional material.

Described herein are integrated circuit devices with conductive regions formed from MX or MAX materials. MAX materials are layered, hexagonal carbides and nitrides that include an early transition metal (M) and an A group element (A). MX materials remove the A group element. MAX and MX materials are highly conductive, and their two-dimensional layer structure allows very thin layers to be formed. MAX or MX materials can be used to form several conductive elements of IC circuits, including contacts, interconnects, or liners or barrier regions for contacts or interconnects.

The invention relates to a method for manufacture of an electrical contact on a structure (10) made of an anisotropic material NA which exhibits an anisotropic electrical conductivity, where the structure (10) exhibits an axial electrical conductivity along a first axis XX′ of the structure (10) and an orthogonal conductivity along a direction YY′ orthogonal to the first axis XX′ of the structure (10), where the orthogonal conductivity is less than the axial conductivity, where the method comprises: a step for the formation of a conductive electrode (20), with an initial thickness Ei, comprising a species M, on a first surface (30) of the structure (10), where the first surface (30) is orthogonal to the orthogonal direction YY′; the method being characterized in that the step for the formation of the conductive electrode (20) is followed by a step for implantation of species X through the conductive electrode (20), into the structure (10).