Correlated Electrical Conductivities to Chemical Configurations of Nitrogenated Nanocrystalline Diamond Films
Date
2022-03-03
Authors
Zkria, Abdelrahman
Gima, Hiroki
Abubakr, Eslam
Mahmoud, Ashraf
Haque, Ariful
Yoshitake, Tsuyoshi
Journal Title
Journal ISSN
Volume Title
Publisher
Multidisciplinary Digital Publishing Institute
Abstract
Diamond is one of the fascinating films appropriate for optoelectronic applications due to its wide bandgap (5.45 eV), high thermal conductivity (3320 W m−1·K−1), and strong chemical stability. In this report, we synthesized a type of diamond film called nanocrystalline diamond (NCD) by employing a physical vapor deposition method. The synthesis process was performed in different ratios of nitrogen and hydrogen mixed gas atmospheres to form nitrogen-doped (n-type) NCD films. A high-resolution scanning electron microscope confirmed the nature of the deposited films to contain diamond nanograins embedded into the amorphous carbon matrix. Sensitive spectroscopic investigations, including X-ray photoemission (XPS) and near-edge X-ray absorption fine structure (NEXAFS), were performed using a synchrotron beam. XPS spectra indicated that the nitrogen content in the film increased with the inflow ratio of nitrogen and hydrogen gas (IN/H). NEXAFS spectra revealed that the σ*C–C peak weakened, accompanied by a π*C=N peak strengthened with nitrogen doping. This structural modification after nitrogen doping was found to generate unpaired electrons with the formation of C–N and C=N bonding in grain boundaries (GBs). The measured electrical conductivity increased with nitrogen content, which confirms the suggestion of structural investigations that nitrogen-doping generated free electrons at the GBs of the NCD films.
Description
Keywords
diamond films, nanodiamond composite, physical vapor deposition, NEXAFS spectra, Ingram School of Engineering
Citation
Zkria, A., Gima, H., Abubakr, E., Mahmoud, A., Haque, A., & Yoshitake, T. (2022). Correlated electrical conductivities to chemical configurations of nitrogenated nanocrystalline diamond films. Nanomaterials, 12(5), 854.