A template-assisted method for the synthesis of 2D nanosheets comprises growing a 2D material on the surface of a nanoparticle substrate that acts as a template for nanosheet growth. The 2D nanosheets may then be released from the template surface, e.g. via chemical intercalation and exfoliation, purified, and the templates may be reused.

A template-assisted method for the synthesis of 2D nanosheets comprises growing a 2D material on the surface of a nanoparticle substrate that acts as a template for nanosheet growth. The 2D nanosheets may then be released from the template surface, e.g. via chemical intercalation and exfoliation, purified, and the templates may be reused.

A transition metal dichalcogenide (TMD) transistor includes a substrate, an n-type two-dimensional (2D) TMD layer, a metal source electrode, a metal drain electrode, and a gate dielectric. The substrate has a top portion that is an insulating layer, and the n-type 2D TMD layer is on the insulating layer. The metal source electrode, the metal drain electrode, and the gate dielectric are on the n-type 2D TMD layer. The metal gate electrode is on top of the gate dielectric and is between the metal source electrode and the metal drain electrode.

A template-assisted method for the synthesis of 2D nanosheets comprises growing a 2D material on the surface of a nanoparticle substrate that acts as a template for nanosheet growth. The 2D nanosheets may then be released from the template surface, e.g. via chemical intercalation and exfoliation, purified, and the templates may be reused.

A process for fabricating a single-crystal semiconductor material of group 13 nitride, in particular GaN, including the steps of: deposition of at least one single-crystal layer by three-dimensional epitaxial growth on a starting substrate, the layer including areas resulting from the growth of basal facets, and areas resulting from the growth of facets of different orientations, called non-basal facets; supply of an n-dopant gas including a first chemical element selected from the chemical elements of group 16 of the periodic table, and at least one second chemical element selected from the chemical elements of group 14 of the periodic table, such that the concentration of the second element in the areas resulting from the growth of the basal facets is higher than 1.0?10.sup.17/cm.sup.3, and the concentration of the first element in the areas resulting from the growth of the non-basal facets is lower than 2.0?10.sup.18/cm.sup.3.

Methods of forming SOI substrates are disclosed. In some embodiments, an epitaxial layer and an oxide layer are formed on a sacrificial substrate. An etch stop layer is formed in the epitaxial layer. The sacrificial substrate is bonded to a handle substrate at the oxide layer. The sacrificial substrate is removed. The epitaxial layer is partially removed until the etch stop layer is exposed.

A method of performing HVPE heteroepitaxy comprises exposing a substrate to a carrier gas, a first precursor gas, a Group II/III element, and ternary-forming gasses (V/VI group precursor), to form a heteroepitaxial growth of a binary, ternary, and/or quaternary compound on the substrate; wherein the carrier gas is H.sub.2, wherein the first precursor gas is HCl, the Group II/III element comprises at least one of Zn, Cd, Hg, Al, Ga, and In; and wherein the ternary-forming gasses comprise at least two or more of AsH.sub.3 (arsine), PH.sub.3 (phosphine), H.sub.2Se (hydrogen selenide), H.sub.2Te (hydrogen telluride), SbH.sub.3 (hydrogen antimonide, or antimony tri-hydride, or stibine), H.sub.2S (hydrogen sulfide), NH.sub.3 (ammonia), and HF (hydrogen fluoride); flowing the carrier gas over the Group II/III element; exposing the substrate to the ternary-forming gasses in a predetermined ratio of first ternary-forming gas to second ternary-forming gas (1tf:2tf ratio); and changing the 1tf:2tf ratio over time.

A transition metal dichalcogenide (TMD) transistor includes a substrate, an n-type two-dimensional (2D) TMD layer, a metal source electrode, a metal drain electrode, and a gate dielectric. The substrate has a top portion that is an insulating layer, and the n-type 2D TMD layer is on the insulating layer. The metal source electrode, the metal drain electrode, and the gate dielectric are on the n-type 2D TMD layer. The metal gate electrode is on top of the gate dielectric and is between the metal source electrode and the metal drain electrode.

After CMP and before an epitaxial growth step, the substrate is prepared by an atmospheric plasma which includes not only a reducing chemistry, but also metastable states of a chemically inert carrier gas. This removes residues, oxides, and/or contaminants. Optionally, nitrogen passivation is also performed under atmospheric conditions, to passivate the substrate surface for later epitaxial growth.

A method of performing HVPE heteroepitaxy comprises exposing a substrate to a carrier gas, a first precursor gas, a Group II/III element, and ternary-forming gasses (V/VI group precursor), to form a heteroepitaxial growth of a binary, ternary, and/or quaternary compound on the substrate; wherein the carrier gas is H.sub.2, wherein the first precursor gas is HCl, the Group II/III element comprises at least one of Zn, Cd, Hg, Al, Ga, and In; and wherein the ternary-forming gasses comprise at least two or more of AsH.sub.3 (arsine), PH.sub.3 (phosphine), H.sub.2Se (hydrogen selenide), H.sub.2Te (hydrogen telluride), SbH.sub.3 (hydrogen antimonide, or antimony tri-hydride, or stibine), H.sub.2S (hydrogen sulfide), NH.sub.3 (ammonia), and HF (hydrogen fluoride); flowing the carrier gas over the Group II/III element; exposing the substrate to the ternary-forming gasses in a predetermined ratio of first ternary-forming gas to second ternary-forming gas (1tf:2tf ratio); and changing the 1tf:2tf ratio over time.