In accordance with an embodiment, a diode comprises a substrate, a dielectric material including an opening that exposes a portion of the substrate, the opening having an aspect ratio of at least 1, a bottom diode material including a lower region disposed at least partly in the opening and an upper region extending above the opening, the bottom diode material comprising a semiconductor material that is lattice mismatched to the substrate, a top diode material proximate the upper region of the bottom diode material, and an active diode region between the top and bottom diode materials, the active diode region including a surface extending away from the top surface of the substrate.

Energy-filtered cold electron devices use electron energy filtering through discrete energy levels of quantum wells or quantum dots that are formed through band bending of tunneling barrier conduction band. These devices can obtain low effective electron temperatures of less than or equal to 45K at room temperature, steep electrical current turn-on/turn-off capabilities with a steepness of less than or equal to 10 mV/decade at room temperature, subthreshold swings of less than or equal to 10 mV/decade at room temperature, and/or supply voltages of less than or equal to 0.1 V.

Energy-filtered cold electron devices use electron energy filtering through discrete energy levels of quantum wells or quantum dots that are formed through band bending of tunneling barrier conduction band. These devices can obtain low effective electron temperatures of less than or equal to 45K at room temperature, steep electrical current turn-on/turn-off capabilities with a steepness of less than or equal to 10 mV/decade at room temperature, subthreshold swings of less than or equal to 10 mV/decade at room temperature, and/or supply voltages of less than or equal to 0.1 V.

A resonant tunneling diode, and other one dimensional electronic, photonic structures, and electromechanical MEMS devices, are formed as a heterostructure in a nanowhisker by forming length segments of the whisker with different materials having different band gaps.

A small-sized frequency-variable terahertz oscillator has a successive and large frequency-sweeping width even at a room temperature. The frequency-variable terahertz oscillator includes a slot antenna, a resonant tunneling diode and a varactor diode arranged parallel to each other along the slot antenna. The frequency-variable terahertz oscillator oscillates in a terahertz frequency range when the resonant tunneling diode and the varactor diode are separately applied with a direct voltage.

A resonant inter-band tunnel diode (RITD) can be fabricated using semiconductor processing similar to that used for Complementary Metal-Oxide-Semiconductor (CMOS) device fabrication, such as can include using silicon. A memory cell (e.g., a random access memory (RAM) cell) can be fabricated to include one or more negative differential resistance device, such as tunneling diodes, such as to provide a single-bit or multi-bit cell. In an example, a hybrid memory cell can be fabricated, such as including one or more negative resistance devices, a MOS transistor structure, and a capacitor structure, such as including an integrated capacitor configuration similar to a generally-available dynamic RAM (DRAM) structure, but such as without requiring a refresh and offering a higher area efficiency.

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.

In accordance with an embodiment, a diode comprises a substrate, a dielectric material including an opening that exposes a portion of the substrate, the opening having an aspect ratio of at least 1, a bottom diode material including a lower region disposed at least partly in the opening and an upper region extending above the opening, the bottom diode material comprising a semiconductor material that is lattice mismatched to the substrate, a top diode material proximate the upper region of the bottom diode material, and an active diode region between the top and bottom diode materials, the active diode region including a surface extending away from the top surface of the substrate.

Structures include a tunneling device disposed over first and second lattice-mismatched semiconductor materials. Process embodiments include forming tunneling devices over lattice-mismatched materials.

A terahertz element of an aspect of the present disclosure includes a semiconductor substrate, first and second conductive layers, and an active element. The first and second conductive layers are on the substrate and mutually insulated. The active element is on the substrate and electrically connected to the first and second conductive layers. The first conductive layer includes a first antenna part extending along a first direction, a first capacitor part offset from the active element in a second direction as viewed in a thickness direction of the substrate, and a first conductive part connected to the first capacitor part. The second direction is perpendicular to the thickness direction and first direction. The second conductive layer includes a second capacitor part, stacked over and insulated from the first capacitor part. The substrate includes a part exposed from the first and second capacitor parts. The first conductive part has a portion spaced apart from the first antenna part in the second direction with the exposed part therebetween as viewed in the thickness direction.