Roles of Hydrogen Atmospheres in Growth of Ultrananocrystalline Diamond by Pulsed Laser Deposition

Kenji Hanada; Takashi Nishiyama; Tsuyoshi Yoshitake; Kunihito Nagayama

doi:10.4028/www.scientific.net/MSF.638-642.1685

Paper Titles

Fatigue Crack Initiation and Propagation at a Sharp Notch in Zr-Based Bulk Metallic Glass
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Glass Formation and Structural Study of Ti₅₀Cu₅₀ Alloy by Molecular Dynamics
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The Role of Casting Temperature in Preparation of Bulk Metallic Glasses
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In Situ Observation of Solidification of Bulk Metallic Glass Forming Alloys from Supercooled Liquid by Using High Energy X-Ray Diffraction Combined with Levitation Techniques
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Roles of Hydrogen Atmospheres in Growth of Ultrananocrystalline Diamond by Pulsed Laser Deposition
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Nanograined Size Pure Iron Elaborated by Means of Spark Plasma Sintering
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Carbon-Based Magnetic Nanocomposite Prepared by Arc-Evaporation of Sm/Co/C System
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Principles of Fabrication of Bulk Ultrafine-Grained and Nanostructured Materials by Multiple Isothermal Forging
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Characterization of FePt Nanopowder Synthesized by a Chemical Vapor Condensation (CVC) Process
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Roles of Hydrogen Atmospheres in Growth of Ultrananocrystalline Diamond by Pulsed Laser Deposition

Abstract:

The growth of ultrananocrystalline diamond (UNCD) by pulsed laser deposition necessitates hydrogen atmospheres during the deposition. Optical emission spectroscopy was used to study the roles of the hydrogen atmosphere on the UNCD growth. Time-resolved images of a plume that expanded from a laser-irradiation spot toward a substrate were taken using a high-speed ICCD camera equipped with narrow-bandpass filters. While the plume disappeared at the longest within 1 s in vacuum, the emission from C+ lasted above the substrate surface for approximately 7 microseconds at a hydrogen pressure of 53.3 Pa. Since emission lifetimes of species are approximately 10 nanoseconds, this implies that C+ ions collided actively for such a long time. The hydrogen atmosphere has a role of forming a high number density of C+ ions. In addition, we believe that atomic hydrogen that might be generated by the collisions with carbon species contributes to the UNCD crystallite formation by their terminating the dangling bonds of carbon clusters as theoretically predicted in previous reports.