Provided are van der Waals (VDW) films comprising one or more transition metal chalcogenide (TMD) films. Also provided are methods of making VDW films. The methods are based on transfer of monolayer TMD films under vacuum, for example, using a handle layer. Also provided are apparatuses and devices comprising one or more VDW film.

Provided are van der Waals (VDW) films comprising one or more transition metal chalcogenide (TMD) films. Also provided are methods of making VDW films. The methods are based on transfer of monolayer TMD films under vacuum, for example, using a handle layer. Also provided are apparatuses and devices comprising one or more VDW film.

A diode is made of a p-type layer and an n-type layer connected in series between a bottom and top electrode. The p-type and n-type layers have a thickness below 20 nm. A p-type dopant concentration and an n-type dopant concentration are high enough to keep a total resistance across the diode at less than 250Ω when the diode is forward biased while still retaining the characteristics of a diode. In some embodiments, the ratio of an ON current to an OFF current is greater than 2.5×10.sup.4. Alternate embodiments of the diode, arrays of diodes and methods of making diodes are disclosed. Example arrays include memory arrays using diodes and phase change memories (PCMs) connected in series as array elements. The arrays can be stacked in layers and can be made/embodied in the back-end-of-the line (BEOL).

Diodes employing one or more Group III-Nitride polarization junctions. A III-N polarization junction may include two III-N material layers having opposite crystal polarities. The opposing polarities may induce a two-dimensional charge sheet (e.g., 2D electron gas) within each of the two III-N material layers. Opposing crystal polarities may be induced through introduction of an intervening layer between two III-N material layers. The intervening layer may be of a material other than a Group III-Nitride. Where a P-i-N diode structure includes two Group III-Nitride polarization junctions, opposing crystal polarities at a first of such junctions may induce a 2D electron gas (2DEG), while opposing crystal polarities at a second of such junctions may induce a 2D hole gas (2DHG). Diode terminals may then couple to each of the 2DEG and 2DHG.

Diodes employing one or more Group III-Nitride polarization junctions. A III-N polarization junction may include two III-N material layers having opposite crystal polarities. The opposing polarities may induce a two-dimensional charge sheet (e.g., 2D electron gas) within each of the two III-N material layers. Opposing crystal polarities may be induced through introduction of an intervening layer between two III-N material layers. The intervening layer may be of a material other than a Group III-Nitride. Where a P-i-N diode structure includes two Group III-Nitride polarization junctions, opposing crystal polarities at a first of such junctions may induce a 2D electron gas (2DEG), while opposing crystal polarities at a second of such junctions may induce a 2D hole gas (2DHG). Diode terminals may then couple to each of the 2DEG and 2DHG.

Gallium nitride based devices and, more particularly to the generation of holes in gallium nitride based devices lacking p-type doping, and their use in light emitting diodes and lasers, both edge emitting and vertical emitting. By tailoring the intrinsic design, a wide range of wavelengths can be emitted from near-infrared to mid ultraviolet, depending upon the design of the adjacent cross-gap recombination zone. The innovation also provides for novel circuits and unique applications, particularly for water sterilization.

The task of the present invention is to achieve gain enhancement. A terahertz device (10) of the present invention includes a terahertz element (20) generating an electromagnetic wave, a dielectric (50) including a dielectric material and surrounding the terahertz element (20), a gas space (92) including a gas, and a reflecting film (82) serving as a reflecting portion. The reflecting film (82) includes a portion opposing the terahertz element (20) through the dielectric (50) and the gas space (92) and reflecting the electromagnetic wave toward a direction, wherein the electromagnetic wave is generated from the terahertz element (20) and transmitted through the dielectric (50) and the gas space (92). In addition, the refractive index of the dielectric (50) is lower than the refractive index of the terahertz element (20) and is higher than the refractive index of the gas in the gas space (92).

The task of the present invention is to achieve gain enhancement. A terahertz device (10) of the present invention includes a terahertz element (20) generating an electromagnetic wave, a dielectric (50) including a dielectric material and surrounding the terahertz element (20), a gas space (92) including a gas, and a reflecting film (82) serving as a reflecting portion. The reflecting film (82) includes a portion opposing the terahertz element (20) through the dielectric (50) and the gas space (92) and reflecting the electromagnetic wave toward a direction, wherein the electromagnetic wave is generated from the terahertz element (20) and transmitted through the dielectric (50) and the gas space (92). In addition, the refractive index of the dielectric (50) is lower than the refractive index of the terahertz element (20) and is higher than the refractive index of the gas in the gas space (92).

Provided is a terahertz light source device including an antenna, a plurality of wire electrodes configured to connect the antenna to a power source, a capacitor connected to the wire electrodes between the antenna and the power source, and a plurality of resonance tunneling diodes connected to the wire electrodes between the capacitor and the antenna, and configured to generate a terahertz wave by coupling with the capacitor as a parallel resonance circuit with respect to the power source.

An oscillator oscillating a tern hertz wave includes a negative resistive element including a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer, with a first conductor, a second conductor, and a dielectric disposed between the first conductor and the second conductor constitutes a resonator, wherein the negative resistive element is disposed between the first conductor and the second conductor, and a layer with a higher resistivity than the first semiconductor layer or the second semiconductor layer, or an amorphous layer is disposed between the negative resistive element and the dielectric.