Measurements of C2 and CH concentrations and temperatures in a dc arc jet using cavity ring-down spectroscopy
Measurements of C2 and CH concentrations and temperatures in a dc arc jet using cavity ring-down spectroscopy
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DOI：
10.1063/1.1505675
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发表时间：
2002-10
影响因子：
3.2
通讯作者：
J. Wills;James A. Smith;W. Boxford;Jmf Elks;M. Ashfold;A. Orr-Ewing
中科院分区：
文献类型：
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作者：
J. Wills;James A. Smith;W. Boxford;Jmf Elks;M. Ashfold;A. Orr-Ewing
本文用腔衰荡光谱法测量了用于化学气相沉积（CVD）多晶金刚石膜的10 kW直流电弧喷射器中C2（α 3 Π uv =0）和CH（X2Π uv =0）自由基的浓度、浓度和温度。从旋转分辨的C2 d3 g-a3 u谱线的强度和宽度得到的气体温度在自由羽流中为3300±200 K，在靠近金刚石薄膜生长的衬底处上升到4800 K。对于1.6kW的输入功率、3.3%CH4/H2比和过量Ar以及50 Torr的压力，通常用于金刚石膜CVD的条件，C2（a）的浓度在离衬底>5 mm的距离处的自由羽流中在6.0±0.2×1012和1.5±0.2×1013 cm-3之间。这些值是假设C2（d-a）光发射的空间分辨研究所暗示的1 cm柱长得出的;扩散反映了电弧喷射焊炬头性能随时间的下降。CH（X）在…
Cavity ring-down spectroscopy has been used to measure the absorbances, concentrations and temperatures of C2(a3Πu v=0) and CH(X2Π v=0) radicals in a ⩽10 kW dc arc jet used for chemical vapor deposition (CVD) of polycrystalline diamond films and operated with CH4/H2/Ar gas mixtures. Gas temperatures derived from the intensities and widths of rotationally resolved C2 d3Πg−a3Πu spectral lines are 3300±200 K in the free plume, rising to ∼4800 K close to the substrate on which the diamond film is grown. For an input power of ∼6 kW, a 3.3% CH4/H2 ratio with excess Ar and a pressure of 50 Torr, the conditions typically employed for diamond film CVD, concentrations of C2(a) are between 6.0±0.2×1012 and 1.5±0.2×1013 cm−3 in the free plume at distances >5 mm from the substrate. These values are derived assuming a 1 cm column length as implied by spatially resolved studies of C2(d−a) optical emission; the spread reflects the decline in performance of the arc jet torch heads over time. The concentration of CH(X) in ...