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Correlation between the Carbon Nanotube Growth Rate and Byproducts in Antenna‐Type Remote Plasma Chemical Vapor Deposition Observed by Vacuum Ultraviolet Absorption Spectroscopy
Author(s) -
Inaba Masafumi,
Ochiai Takumi,
Ohara Kazuyoshi,
Kato Ryogo,
Maki Tasuku,
Ohashi Toshiyuki,
Kawarada Hiroshi
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201901504
Subject(s) - chemical vapor deposition , carbon nanotube , materials science , plasma , absorption (acoustics) , absorption spectroscopy , antenna (radio) , ultraviolet , carbon nanotube quantum dot , vacuum ultraviolet , plasma enhanced chemical vapor deposition , optoelectronics , analytical chemistry (journal) , photochemistry , chemical engineering , nanotechnology , nanotube , atomic physics , chemistry , optics , environmental chemistry , composite material , physics , engineering , quantum mechanics , telecommunications , computer science
For sp 2 or sp 3 carbon material growth, it is important to investigate the precursors or intermediates just before growth. In this study, the density of ethylene (C 2 H 4 ) outside the plasma discharge space and just before reaching the carbon nanotube (CNT) growth region is investigated by vacuum ultraviolet absorption spectroscopy for plasma discharge in an antenna‐type remote plasma chemical vapor deposition with a CH 4 /H 2 system, with which the growth of very long (≈0.5 cm) CNT forests is achieved. Single‐wall CNT forests have the potential for application as electrodes in battery cells, vertical wiring for high current applications, and thermal interface materials. It is observed that the plasma discharge decomposes the CH 4 source gas and forms C 2 H x species, which reversibly reform to C 2 H 4 in the plasma‐off state. In addition, the density of the formed C 2 H 4 has a strong correlation to the CNT growth rate. Therefore, the C 2 H 4 density is a good indicator of the density of C 2 H x species for CNT growth in the CH 4 /H 2 plasma system.