Wisconsin Alumni Research Foundation

University of New Mexico

Stc.unm

Francesca Cavallo

Max G Lagally

Daniel Warren Van Der Weide

Abhishek Bhat

Vijay Saradhi Mangu

Matthew McLean Dwyer

Richard Rojas-Delgado

Divya Jyoti Prakash

Traveling-wave tube amplifiers for high-frequency signals, including terahertz signals, and methods for making a slow-wave structure for the traveling-wave tube amplifiers are provided. The slow-wave structures include helical conductors that are self-assembled via the release and relaxation of strained films from a sacrificial growth substrate.

Methods of making a self-assembled slow-wave structures

Traveling-wave tube amplifiers and methods for making slow-wave structures for the amplifiers are provided. The SWSs include helical conductors that are self-assembled via the release of stressed electrically conductive strips from a sacrificial material. The helical conductors can be electroplated post-self-assembly to fortify the helix, reduce losses, and tailor the dimensions and operating parameters of the helix.

Electroplated helical slow-wave structures for high-frequency signals

Traveling wave tube amplifier having a helical slow-wave structure supported by a cylindrical scaffold

Methods for fabricating thin, high-aspect-ratio Ge nanostructures from high-quality, single-crystalline Ge substrates are provided. Also provided are grating structures made using the methods. The methods utilize a thin layer of graphene between a surface of a Ge substrate, and an overlying resist layer. The graphene passivates the surface, preventing the formation of water-soluble native Ge oxides that can result in the lift-off of the resist during the development of the resist.

Arrays of high-aspect-ratio germanium nanostructures with nanoscale pitch and methods for the fabrication thereof

A self-assembling element fabricated using integrated circuit techniques may provide a small diameter helical conductor surrounding an electron beam for the construction of a vacuum electronic device such as a traveling-wave tube for terahertz scale signal.

High-frequency vacuum electronic device

A solar cell for collecting solar radiation can include a barrier layer such as a dielectric barrier layer and a heterostructure including a first light absorbing layer and at least a second light absorbing layer. A method for forming the solar cell can include forming a sacrificial layer on a support substrate and forming the barrier layer on the sacrificial layer. The barrier layer is formed to have a strain gradient through its thickness. The heterostructure is attached to the barrier layer and the sacrificial layer is removed, thereby separating the barrier layer and the heterostructure from the support substrate. During the removal of the sacrificial layer, the strain gradient causes the barrier layer and heterostructure, to roll, curl, or spiral, thereby resulting in a radially stacked heterostructure that provides a light concentrating optical cavity having multiple light absorbing layers with different band gaps.

Radially stacked solar cells based on 2D atomic crystals and methods for their production

Electrically conductive material structures, analog electronic devices incorporating the structures and methods for making the structures are provided. The structures include a layer of graphene on a semiconductor substrate. The graphene layer and the substrate are separated by an interfacial region that promotes transfer of charge carriers from the surface of the substrate to the graphene.

Graphene-on-semiconductor substrates for analog electronics

Electronic devices for the generation of electromagnetic radiation are provided. Also provided are methods for using the devices to generate electromagnetic radiation. The radiation sources include an anisotropic electrically conducting thin film that is characterized by a periodically varying charge carrier mobility in the plane of the film. The periodic variation in carrier mobility gives rise to a spatially varying electric field, which produces electromagnetic radiation as charged particles pass through the film.

Growing community of inventors

Corrales, NM, United States of America

Francesca Cavallo