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Hollow cathode sustained plasma microjets: Characterization and application to diamond deposition

Sankaran, R. Mohan and Giapis, Konstantinos P. (2002) Hollow cathode sustained plasma microjets: Characterization and application to diamond deposition. Journal of Applied Physics, 92 (5). pp. 2406-2411. ISSN 0021-8979. doi:10.1063/1.1497719.

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Extending the principle of operation of hollow cathode microdischarges to a tube geometry has allowed the formation of stable, high-pressure plasma microjets in a variety of gases including Ar, He, and H2. Direct current discharges are ignited between stainless steel capillary tubes (d = 178 µm) which are operated as the cathode and a metal grid or plate that serves as the anode. Argon plasma microjets can be sustained in ambient air with plasma voltages as low as 260 V for cathode-anode gaps of 0.5 mm. At larger operating voltage, this gap can be extended up to several millimeters. Using a heated molybdenum substrate as the anode, plasma microjets in CH4/H2 mixtures have been used to deposit diamond crystals and polycrystalline films. Micro-Raman spectroscopy of these films shows mainly sp3 carbon content with slight shifting of the diamond peak due to internal stresses. Optical emission spectroscopy of the discharges used in the diamond growth experiments confirms the presence of atomic hydrogen and CH radicals.

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Giapis, Konstantinos P.0000-0002-7393-298X
Additional Information:© 2002 American Institute of Physics. (Received 11 April 2002; accepted 10 June 2002) The authors are grateful to Elizabeth Arredondo for technical assistance with the micro-Raman spectra. Useful discussions with R. C. Flagan are also acknowledged. This material was based on work supported by NSF (ECS-9729968).
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Subject Keywords:diamond; plasma deposition; discharges (electric); Raman spectra; internal stresses
Issue or Number:5
Record Number:CaltechAUTHORS:SANjap02
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3004
Deposited By: Archive Administrator
Deposited On:10 May 2006
Last Modified:08 Nov 2021 19:52

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