Improvement in plasma illumination properties of ultrananocrystalline diamond films by grain boundary engineering
學年 102
學期 1
出版（發表）日期 2013-08-01
作品名稱 Improvement in plasma illumination properties of ultrananocrystalline diamond films by grain boundary engineering
作品名稱（其他語言）
著者 K. J. Sankaran; K. Srinivasu; Chen, H. C.; Dong, C. L.; Leou, K. C.; Lee, C. Y.; Tai, N. H.; Lin, I. N.
單位 淡江大學物理學系
出版者 College Park: American Institute of Physics
著錄名稱、卷期、頁數 Journal of Applied Physics 114(5), 054304(11pages)
摘要 Microstructural evolution of ultrananocrystalline diamond (UNCD) films as a function of substrate temperature (TS) and/or by introducing H2 in Ar/CH4 plasma is investigated. Variation of the sp 2 and sp 3 carbon content is analyzed using UV-Raman and near-edge X-ray absorption fine structure spectra. Morphological and microstructural studies confirm that films deposited using Ar/CH4 plasma at low TS consist of a random distribution of spherically shaped ultra-nano diamond grains with distinct sp 2-bonded grain boundaries, which are attributed to the adherence of CH radicals to the nano-sized diamond clusters. By increasing TS, adhering efficiency of CH radicals to the diamond lattice drops and trans-polyacetylene (t-PA) encapsulating the nano-sized diamond grains break, whereas the addition of 1.5% H2 in Ar/CH4 plasma at low TS induces atomic hydrogen that preferentially etches out the t-PA attached to ultra-nano diamond grains. Both cases make the sp 3-diamond phase less passivated. This leads to C2 radicals attaching to the diamond lattice promoting elongated clustered grains along with a complicated defect structure. Such a grain growth model is highly correlated to explain the technologically important functional property, namely, plasma illumination (PI) of UNCD films. Superior PI properties, viz. low threshold field of 0.21 V/μm with a high PI current density of 4.10 mA/cm2 (at an applied field of 0.25 V/μm) and high γ-coefficient (0.2604) are observed for the UNCD films possessing ultra-nano grains with a large fraction of grain boundary phases. The grain boundary component consists of a large amount of sp 2-carbon phases that possibly form interconnected paths for facilitating the transport of electrons and the electron field emission process that markedly enhance PI properties.
關鍵字
語言 en
ISSN 0021-8979 1089-7550
期刊性質 國外
收錄於
產學合作
通訊作者
審稿制度 是
國別 USA
公開徵稿
出版型式 ,電子版,紙本
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