Doped Diamond CVD System for Emission Diodes for High Power Electron Beams
Abstract
This proposal is for the purchase of a custom microwave plasma enhanced chemical vapor deposition (MPCVD) system specifically for phosphorus doped, n-type epitaxial diamond. The proposed CVD system is expected to provide P-doped diamond layers with high doping concentrations and low impurity compensation that will enable fabrication of a new class of diamond diodes for electron emission. This deposition system will be used to develop a novel device technology to act as a cathode for compact high power rf and microwave devices recently funded by ONR. This project is a collaboration between the Johns Hopkins University Applied Physics Laboratory and Arizona State University. By reducing dopant compensation the new system design could achieve greater than a factor of 5 improvement in current density. The device operating principle is direct electron emission from a 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 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. 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. The new system will directly impact the education goals of graduate and undergraduate students involved with ONR funded research and energy and power electronics projects supported by DoD and ARPA-E. In addition, students from these projects will support the ASU Sundial program, which was established to enhance the success of physical science students, particularly traditionally underrepresented students.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 03, 2017
- Source ID
- N000141713002
Entities
People
- Robert J. Nemanich
Organizations
- Arizona State University
- Office of Naval Research
- United States Navy