Diamond Emission Diodes for High Power Electron Beams

Project: Research project

Description

This project proposes to develop a novel device technology to act as a cathode for vacuum-electronic devices. The device operating principle is direct electron emission from forward biased diamond p-i-n diode. In this device, the combination of high material quality, negative electron affinity, and device geometry allows a large fraction of the current driven through the diode to be emitted directly into the vacuum. The basic device geometry consists of an n-type layer at the top followed by an intrinsic layer and finally a p-type layer on the bottom. The device is patterned into narrow fins and the electrons are injected downwards through the n layer, leaving the device through the intrinsic region which forms the fin sidewalls. This device combines the best attributes of the competing technologies thermionic emitters and field emitters. It offers the longevity of thermionic emitters, operates at a temperature close to that of field-emitters, and allows micron-scale lithographic patterning of the emission region like field emitters. This lithographic patterning makes the devices much more suited to integration into vacuum electronic devices, as the electron beam shape can be defined by the emitter, which for many vacuum electronic system geometries allows for a much more compact system, because it eliminates the need for complex beam shaping electrodes.

The research is directed towards demonstrating a revolutionary technology that would provide a cathode structure based on epitaxial diamond electron emission diodes with a current densities on the order of 10 A/cm2, an emission efficiency of 5%, an emission uniformity of better than 10%, and an operation temperature of less than 500 C.

This research will be a combined effort by both Arizona State University and the JHU Applied Physics Laboratory, with both parties bringing critical expertise to the table. ASU is a technology leader in chemical vapor deposition of high quality doped diamond films. Their work to date will form the foundation for this research. The JHU-APL is recognized for its hands-on, operational expertise in research, analysis, design, prototype development, and testing. It will leverage significant expertise in semiconductor device physics, electron emission, and prototype development in order to realize the proposed p-i-n diamond diodes.
StatusFinished
Effective start/end date8/1/167/31/19

Funding

  • DOD-NAVY: Office of Naval Research (ONR): $495,000.00

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diamonds
diodes
electron beams
emitters
thermionic emitters
electron emission
vacuum
fins
geometry
cathodes
prototypes
electronics
APL (programming language)
negative electron affinity
p-i-n diodes
design analysis
physics
diamond films
semiconductor devices
vapor deposition