Influence of Surface Properties on the Quantum Photoyield of Diamond Photocathodes

• Published in: Physica status solidi. A, Applied research Vol. 186; no. 2; pp. 227 - 233
• Main Authors: Foord, J.S., Wang, Jun, Hian Lau, Chi, Hiramatsu, Mineo, Vickers, J., Jackman, R.B.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin WILEY-VCH Verlag Berlin GmbH 01-08-2001; WILEY‐VCH Verlag Berlin GmbH; Wiley-VCH
• Subjects: 73.20.At; 73.50.Pz; 79.60.Bm; Adsorbed layers and thin films; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Photoemission and photoelectron spectra; Physics; Chemical stability; Diamonds; Doped materials; Experimental study; Photocathodes; Thin films; CVD; Quantum efficiency; Hydrogen additions; Surface properties; Boron additions; Photoelectron emission; Oxidation; X-ray photoelectron spectra
• ISSN: 0031-8965; 1521-396X
• DOI: 10.1002/1521-396X(200108)186:2<227::AID-PSSA227>3.0.CO;2-M

The quantum efficiency and chemical stability of CVD diamond photocathodes has been examined. As‐grown or microwave plasma hydrogenated boron‐doped diamond films display a quantum photoyield of approximately 0.05% at 190 nm, which degrades gradually as the material is left in ambient atmosphere, due to slow oxidation. Rapid degradation in performance occurs when exposed to atomic or electronically excited oxygen. X‐ray photoelectron spectroscopy shows that the yield drops close to zero at around monolayer oxygen coverage, and that the main oxygen species on the surface is hydroxyl or isolated ether linkages.