A method for coating a substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The plasma ball has a diameter. The plasma ball is disposed at a first distance from the substrate and the substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the substrate, and a diamond coating is deposited on the substrate. The diamond coating has a thickness. Furthermore, the diamond coating has an optical transparency of greater than about 80%. The diamond coating can include nanocrystalline diamond. The microwave plasma source can have a frequency of about 915 MHz.

Using processes disclosed herein, materials and structures are created and used. For example, processes can include melting amorphous carbon doped with nitrogen and carbon-13 into an undercooled state followed by quenching. Materials disclosed herein may include dopants in concentrations exceeding thermodynamic solubility limits.

A semiconductor device and method of formation are provided. The semiconductor device includes a substrate, a first active area over the substrate, a second active area over the substrate, a graphene channel between the first active area and the second active area, and a first in-plane gate. In some embodiments, the graphene channel, the first in-plane gate, the first active area, and the second active area include graphene. A method of forming the first in-plane gate, the first active area, the second active area, and the graphene channel from a single layer of graphene is also provided.

Boron-doped diamond and methods for making it are provided. The doped diamond is made using an ultra-thin film of heavily boron-doped silicon as a dopant carrying material in a low temperature thermal diffusion doping process.

A method of forming electrical contacts on a diamond substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The mixture of gases include a source of a p-type or an n-type dopant. The plasma ball is disposed at a first distance from the diamond substrate. The diamond substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the diamond substrate for a first time, and a UNCD film, which is doped with at least one of a p-type dopant and an n-type dopant, is disposed on the diamond substrate. The doped UNCD film is patterned to define UNCD electrical contacts on the diamond substrate.

A photodetector includes an insulating layer on a substrate, a first graphene layer on the insulating layer, a 2-dimensional (2D) material layer on the first graphene layer, a second graphene layer on the 2D material layer, a first electrode on the first graphene layer, and a second electrode on the second graphene layer. The 2D material layer includes a barrier layer and a light absorption layer. The barrier layer has a larger bandgap than the light absorption layer.

The semiconductor device of the present invention includes a first conductivity type semiconductor layer made of a wide bandgap semiconductor and a Schottky electrode formed to come into contact with a surface of the semiconductor layer, and has a threshold voltage V.sub.th of 0.3 V to 0.7 V and a leakage current J.sub.r of 110.sup.9 A/cm.sup.2 to 110.sup.4 A/cm.sup.2 in a rated voltage V.sub.R.

A method can be used for manufacturing a metal substrate structure for a semiconductor power module. A plurality of terminals are welded to a metal top layer. After the welding, a dielectric layer is coupled between the metal top layer and a metal bottom layer. The dielectric can be laminated or molded, as examples.

A two-dimensional heterostructure is synthesized by producing a patterned first two-dimensional material on a growth substrate. The first two-dimensional material is patterned to define at least one void through which an exposed region of the growth substrate is exposed. Seed molecules are selectively deposited either on the exposed region of the growth substrate or on the patterned first two-dimensional material. A second two-dimensional material that is distinct from the first two-dimensional material is then grown from the deposited seed molecules.

A photodetector includes an insulating layer on a substrate, a first graphene layer on the insulating layer, a 2-dimensional (2D) material layer on the first graphene layer, a second graphene layer on the 2D material layer, a first electrode on the first graphene layer, and a second electrode on the second graphene layer. The 2D material layer includes a barrier layer and a light absorption layer. The barrier layer has a larger bandgap than the light absorption layer.