Achieving a Large Net "Negative Electron Affinity" on Diamond (100) via Molecular Oxygen and Lithium...

Area of Science:

• Materials Science
• Surface Science
• Solid State Physics

Background:

• Achieving stable negative electron affinity (NEA) diamond surfaces is essential for high-performance electron emission devices.
• Surface engineering is key to developing thermally and ambient-stable diamond surfaces for next-generation electronics and energy applications.

Purpose of the Study:

• To develop and investigate a novel "molecular oxygen" oxidation method for (100)-oriented single-crystal diamond.
• To compare the performance of this new method against the established UV-ozone treatment for NEA diamond surfaces.

Main Methods:

• Utilized state-of-the-art surface analysis techniques to quantify oxygen coverage.
• Characterized the electronic structure of diamond surfaces after lithium deposition.
• Compared molecular oxygen oxidation with UV-ozone treatment.

Main Results:

• The molecular oxygen treatment achieved approximately 90% surface oxygen coverage.
• This method produced an NEA of -1.68 eV, surpassing the UV-ozone method's -1.31 eV.
• While air stability was slightly limited, the NEA was recoverable upon reactivation to -1.56 eV.

Conclusions:

• The novel molecular oxygen treatment offers a practical and high-performance route to optimized NEA diamond surfaces.
• This scalable platform is suitable for developing next-generation electronic and energy applications.
• The developed method advances the realization of stable NEA diamond for electron emission devices.