2020/07/01 by Gregory J Smith, Smith, Gregory J., James Ellis +17
Engineering · Materials Science · #Diamond and Carbon-based Materials Research #FOS: Physical sciences #Ion-surface interactions and analysis #Metal and Thin Film Mechanics #Plasma Physics (physics.plasm-ph)
paper · pdf · doi:10.48550/arxiv.2007.00614
openalex publication_date 2020/07/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The production of negative ions is of significant interest for applications\nincluding mass spectrometry, particle acceleration, material surface\nprocessing, and neutral beam injection for magnetic confinement fusion. Methods\nto improve the efficiency of the surface production of negative ions, without\nthe use of low work function metals, are of interest for mitigating the complex\nengineering challenges these materials introduce. In this study we investigate\nthe production of negative ions by doping diamond with nitrogen. Negatively\nbiased (-20 V or -130 V), nitrogen doped micro-crystalline diamond films\nare introduced to a low pressure deuterium plasma (helicon source operated in\ncapacitive mode, 2 Pa, 26 W) and negative ion energy distribution functions\n(NIEDFs) are measured via mass spectrometry with respect to the surface\ntemperature (30\∘C to 750\∘C) and dopant concentration. The\nresults suggest that nitrogen doping has little influence on the yield when the\nsample is biased at -130 V, but when a relatively small bias voltage of -20\nV is applied the yield is increased by a factor of 2 above that of un-doped\ndiamond when its temperature reaches 550\∘C. The doping of diamond with\nnitrogen is a new method for controlling the surface production of negative\nions, which continues to be of significant interest for a wide variety of\npractical applications.\n