Impact of surface treatments on the electron affinity of nitrogen-doped ultrananocrystalline diamond

Fuente: arXiv
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Main Authors: Chambers, Andre, McCloskey, Daniel J., Dontschuk, Nikolai, Hashem, Hassan N. Al, Murdoch, Billy J., Stacey, Alastair, Prawer, Steven, Ahnood, Arman
Format: Preprint
Published: 2024
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author Chambers, Andre
McCloskey, Daniel J.
Dontschuk, Nikolai
Hashem, Hassan N. Al
Murdoch, Billy J.
Stacey, Alastair
Prawer, Steven
Ahnood, Arman
author_facet Chambers, Andre
McCloskey, Daniel J.
Dontschuk, Nikolai
Hashem, Hassan N. Al
Murdoch, Billy J.
Stacey, Alastair
Prawer, Steven
Ahnood, Arman
contents In recent years, various forms of nanocrystalline diamond (NCD) have emerged as an attractive group of diamond/graphite mixed-phase materials for a range of applications from electron emission sources to electrodes for neural interfacing. To tailor their properties for different uses, NCD surfaces can be terminated with various chemical functionalities, in particular hydrogen and oxygen, which shift the band edge positions and electron affinity values. While the band edge positions of chemically terminated single crystal diamond are well understood, the same is not true for nanocrystalline diamond, which has uncontrolled crystallographic surfaces with a variety of chemical states as well as graphitic grain boundary regions. In this work, the relative band edge positions of as-grown, hydrogen terminated, and oxygen terminated nitrogen-doped ultrananocrystalline diamond (N-UNCD) are determined using ultraviolet photoelectron spectroscopy (UPS), while the band bending is investigated using photoelectrochemical measurements. In contrast to the widely reported negative electrode affinity of hydrogen terminated single crystal diamond, our work demonstrates that hydrogen terminated N-UNCD exhibits a positive electron affinity owing to the increased surface and bulk defect densities. These findings elucidate the marked differences in electrochemical properties of hydrogen and oxygen terminated N-UNCD, such as the dramatic changes in electrochemical capacitance.
format Preprint
id arxiv_https___arxiv_org_abs_2406_15521
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Impact of surface treatments on the electron affinity of nitrogen-doped ultrananocrystalline diamond
Chambers, Andre
McCloskey, Daniel J.
Dontschuk, Nikolai
Hashem, Hassan N. Al
Murdoch, Billy J.
Stacey, Alastair
Prawer, Steven
Ahnood, Arman
Applied Physics
Materials Science
In recent years, various forms of nanocrystalline diamond (NCD) have emerged as an attractive group of diamond/graphite mixed-phase materials for a range of applications from electron emission sources to electrodes for neural interfacing. To tailor their properties for different uses, NCD surfaces can be terminated with various chemical functionalities, in particular hydrogen and oxygen, which shift the band edge positions and electron affinity values. While the band edge positions of chemically terminated single crystal diamond are well understood, the same is not true for nanocrystalline diamond, which has uncontrolled crystallographic surfaces with a variety of chemical states as well as graphitic grain boundary regions. In this work, the relative band edge positions of as-grown, hydrogen terminated, and oxygen terminated nitrogen-doped ultrananocrystalline diamond (N-UNCD) are determined using ultraviolet photoelectron spectroscopy (UPS), while the band bending is investigated using photoelectrochemical measurements. In contrast to the widely reported negative electrode affinity of hydrogen terminated single crystal diamond, our work demonstrates that hydrogen terminated N-UNCD exhibits a positive electron affinity owing to the increased surface and bulk defect densities. These findings elucidate the marked differences in electrochemical properties of hydrogen and oxygen terminated N-UNCD, such as the dramatic changes in electrochemical capacitance.
title Impact of surface treatments on the electron affinity of nitrogen-doped ultrananocrystalline diamond
topic Applied Physics
Materials Science
url https://arxiv.org/abs/2406.15521