A semiconductor device includes a substrate, a two-dimensional (2D) material layer formed on the substrate and having a first region and a second region adjacent to the first region, and a source electrode and a drain electrode provided to be respectively in contact with the first region and the second region of the 2D material layer, the second region of the 2D material layer including an oxygen adsorption material layer in which oxygen is adsorbed on a surface of the second region.

A semiconductor device comprises an active region and a passive region located outside the active region. The active region comprises a plurality of active region units. At least one pair of adjacent active region units do not completely overlap in a length direction of the semiconductor device.

A method including forming a diamond material on the surface of a substrate; forming a first contact and a separate second contact; and patterning the diamond material to form a nanowire between the first contact and the second contact. An apparatus including a first contact and a separate second contact on a substrate; and a nanowire including a single crystalline or polycrystalline diamond material on the substrate and connected to each of the first contact and the second contact.

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.

A plate varactor includes a dielectric substrate and a first electrode embedded in a surface of the substrate. A capacitor dielectric layer is disposed over the first electrode, and a layer of graphene is formed over the dielectric layer to contribute a quantum capacitance component to the dielectric layer. An upper electrode is formed on the layer of graphene. Other embodiments and methods for fabrication are also included.

According to one embodiment, a semiconductor device includes a first and second electrode, a first, second, third and fourth semiconductor region, and a first intermediate metal film. The first region is provided above the first electrode and has a first impurity concentration. The second region is provided above the first region and has a second impurity concentration lower than the first impurity concentration. The third region is provided above the second region and has a third impurity concentration. The fourth region is provided above the second region and has a fourth impurity concentration lower than the third impurity concentration. The second electrode is provided above the third region and the fourth region and is in ohmic contact with the third region. The intermediate metal film is provided between the second electrode and the fourth region. The intermediate metal film forms Schottky junction with the fourth region.

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.

Temperature sensor devices and corresponding methods are provided. A temperature sensor may include a first layer being essentially non-conductive in a temperature range and a second layer having a varying resistance in the temperature range.

A p-type anode layer (2) is provided on an upper surface of an n-type drift layer (1). An n-type cathode layer (3) is provided on a lower surface of the n.sup.-type drift layer (1). An n-type buffer layer (4) is provided between the n.sup.-type drift layer (1) and the n-type cathode layer (3). A peak impurity concentration in the n-type buffer layer (4) is higher than that in the n.sup.-type drift layer (1) and lower than that in the n-type cathode layer (3). A gradient of carrier concentration at a connection between the n.sup.-type drift layer (1) and the n-type buffer layer (4) is 20 to 2000 cm.sup.4.

A semiconductor device of the present invention includes a semiconductor layer of a first conductivity type having a cell portion and an outer peripheral portion disposed around the cell portion, and a surface insulating film disposed in a manner extending across the cell portion and the outer peripheral portion, and in the cell portion, formed to be thinner than a part in the outer peripheral portion.