A vertical transistor structure having a metal gate wordline. The vertical transistor structure can include an epitaxially grown semiconductor column surrounded by a thin gate dielectric layer. A gate structure can surround the semiconductor column and the gate dielectric layer. The device can include first and second dielectric layers and an electrically conductive metal layer located between the first and second dielectric layers. The electrically conductive metal of the gate structure can be tungsten (W). In addition, a thin layer of Ti or TiN can be formed between the metal gate layer and the first and second dielectric layers and the gate dielectric layer. The metal gate layer can be formed with or without the use of a sacrificial layer.

A vertical transistor structure having a metal gate wordline. The vertical transistor structure can include an epitaxially grown semiconductor column surrounded by a thin gate dielectric layer. A gate structure can surround the semiconductor column and the gate dielectric layer. The device can include first and second dielectric layers and an electrically conductive metal layer located between the first and second dielectric layers. The electrically conductive metal of the gate structure can be tungsten (W). In addition, a thin layer of Ti or TiN can be formed between the metal gate layer and the first and second dielectric layers and the gate dielectric layer. The metal gate layer can be formed with or without the use of a sacrificial layer.

Disclosed herein are transistor source/drain contacts, and related methods and devices. For example, in some embodiments, a transistor may include a channel and a source/drain contact, wherein the source/drain contact includes an interface material and a bulk material, the bulk material has a different material composition than the interface material, the interface material is between the bulk material and the channel, the interface material includes indium and an element different from indium, and the element is aluminum, vanadium, zirconium, magnesium, gallium, hafnium, silicon, lanthanum, tungsten, or cadmium.

Disclosed herein are transistor source/drain contacts, and related methods and devices. For example, in some embodiments, a transistor may include a channel and a source/drain contact, wherein the source/drain contact includes an interface material and a bulk material, the bulk material has a different material composition than the interface material, the interface material is between the bulk material and the channel, the interface material includes indium and an element different from indium, and the element is aluminum, vanadium, zirconium, magnesium, gallium, hafnium, silicon, lanthanum, tungsten, or cadmium.

A diode includes an n-type semiconductor layer including an n-type Ga.sub.2O.sub.3-based single crystal, and a p-type semiconductor layer including a p-type semiconductor in which a volume of an amorphous portion is higher than a volume of a crystalline portion. The n-type semiconductor layer and the p-type semiconductor layer form a pn junction.

Embodiments of this disclosure include apparatus, systems, and methods for fabricating monolayers. In one example, a method includes forming a multilayer film having a plurality of monolayers of a two-dimensional (2D) material on a growth substrate. The multilayer film has a first side proximate the growth substrate and a second side opposite the first side.

Embodiments of this disclosure include apparatus, systems, and methods for fabricating monolayers. In one example, a method includes forming a multilayer film having a plurality of monolayers of a two-dimensional (2D) material on a growth substrate. The multilayer film has a first side proximate the growth substrate and a second side opposite the first side.

A method of fabricating a semiconductor device includes forming a semiconductor layer, the semiconductor layer including a two-dimensional semiconductor material, forming a sacrificial layer on the semiconductor layer, forming a metal contact layer on the sacrificial layer, and removing the sacrificial layer. After the sacrificial layer is removed, the semiconductor layer and the metal contact layer are bonded to each other through a van der Waals bond.

A method of fabricating a semiconductor device includes forming a semiconductor layer, the semiconductor layer including a two-dimensional semiconductor material, forming a sacrificial layer on the semiconductor layer, forming a metal contact layer on the sacrificial layer, and removing the sacrificial layer. After the sacrificial layer is removed, the semiconductor layer and the metal contact layer are bonded to each other through a van der Waals bond.

Methods and materials for growing TMD materials on substrates and making semiconductor devices are described. Metal contacts may be created prior to conducting a deposition process such as chemical vapor deposition (CVD) to grow a TMD material, such that the metal contacts serve as the seed/catalyst for TMD material growth. A method of making a semiconductor device may include conducting a lift-off lithography process on a substrate to produce a substrate having metal contacts deposited thereon in lithographically defined areas, and then growing a TMD material on the substrate by a deposition process to make a semiconductor device. Further described are semiconductor devices having a substrate with metal contacts deposited thereon in lithographically defined areas, and a TMD material on the substrate, where the TMD material is a continuous, substantially uniform monolayer film between and on the metal contacts, where the metal contacts are chemically bonded to the TMD material.