SiGe is one of the best thermoelectric materials for high temperature applications. Superlattice structures can further enhance the thermoelectric properties by reducing the thermal conductivity and by increasing the Seebeck coefficient via selective emission of hot electrons through thermionic emission. SiGe/Si superlattice structures were grown on a silicon wafer using molecular beam epitaxy....

Thermionic emission in heterostructures is investigated for integrated cooling of high power electronic and optoelectronic devices. This evaporative cooling is achieved by selective emission of hot electrons over a barrier layer from the cathode to the anode. As the energy distribution of emitted electrons is almost exclusively on one side of Fermi energy, upon the current flow, strong carrier-...

The surface temperature of a tungsten facing hot hydrogen plasma is evaluated, thanks to 1d/3v particle-in-cell simulations in floating wall conditions. At each iteration, the heat flux cathode equalized with outgoing one, which due thermionic emission, radiation, and conduction through wall. thermal conductivity chosen within range 35–160 W m−1 K−1 different order take into account condition. ...

We study two techniques to create electrons in a liquid helium environment. One is thermionic emission of tungsten filaments in a low temperature cell in the vapor phase with a superfluid helium film covering all surfaces; the other is operating a glowing filament immersed in bulk liquid helium. We present both the steady state and rapid sweep I-V curves and the electron current yield. These cu...

The 3D finite-element gun and collector modeling code, MICHELLE, has been under development at SAIC in collaboration with industrial partners and national laboratories (ref. 1). This development program has been designed to address the shortcomings of current beam optics simulation and modeling tools for vacuum electron devices. The program specifically targets problem classes including gridded...

Arc and glow discharges are defined based on their cathode processes. Arcs are characterized by collective electron emission, which can be stationary with hot cathodes (thermionic arcs), or nonstationary with cold cathodes (cathodic arcs). A brief review on cathodic arc properties serves as the starting point to better understand arcing phenomena in sputtering. Although arcing occurs in both me...