Record diamond results could show the future of power electronics

Image illustrating an atomically thin surface modification and electron extraction. Originally published in Photoelectron emission from lithiated diamond, O'Donnell, Physical Status Solidi (a), Volume 211. Copyright 2014 John Wiley & Sons Ltd

The green bar demonstrates the large negative electron affinity (NEA) achieved in this study as compared to previous research.

Researchers recently recorded the largest reported negative electron affinity (NEA) to date on diamond using magnesium adsorption on a previously oxygen-terminated surface.

The large NEA and low work function will allow a very high electron yield from diamond. This surface modification can be used to make better microelectronic devices that rely on extracting electrons, such as high-power vacuum diodes (used in power electronics). Other practical applications of this work include highly sensitive light detectors (used in devices such as night vision goggles) and even the potential for using diamond as an electron source in liquids to help chemists create sophisticated reactions more easily.

Starting with a single crystal of diamond grown at MCN, the research team created an atomically thin layer of magnesium atoms attached to the diamond with oxygen atoms. The magnesium layer lowered the energy required to extract electrons from the diamond, while the oxygen atoms kept the structure robust. The team measured the resulting structure at the Soft X-Ray Spectroscopy beamline at the Australian Synchrotron.

As well as resulting in a very high NEA, the process undertaken by the team was notable for its straightforward application and producing a surface that can withstand exposure to air and water immersion without significant degradation. The simplicity of the process will allow surface processing to be easily incorporated into the manufacturing of electronic devices and should also result in longer device lifespan.

Read the original article in Physical Review B here: Extremely high negative electron affinity of diamond via magnesium adsorption - Phys. Rev. B 92, 035303 – Published 16 July 2015