Kalanyan Berc, Maslar James E
Material Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Drive., Gaithersburg, Maryland 20899, United States.
J Phys Chem A. 2024 Jan 11;128(1):118-128. doi: 10.1021/acs.jpca.3c06522. Epub 2023 Dec 28.
This article reports quantitative absorption spectra for MoCl, MoOCl, and MoOCl in the vapor phase from 45,500 to 15,500 cm (645 to 220 nm). Spectra are obtained in an ultrahigh purity stainless steel vacuum system by rapidly sampling a range of analyte partial pressures. The short measurement times and the differential absorbance method employed here minimize effects from uncontrolled transients such as window deposits. A detailed analysis of replicate measurements and time-resolved spectra shows generally reproducible spectral response from MoCl vapors at 120 °C. The presence of HCl and MoOCl impurities in the MoCl vapor samples is determined to be unlikely based on the analysis of absorbance-pressure curves and spectral peak fitting. Comparison with MoOCl and MoOCl spectra shows a unique spectral fingerprint for MoCl at 28,500 cm providing a convenient means of discriminating between MoCl and its oxychlorides in the visible wavelengths. Adsorption behavior of MoCl on surfaces is also discussed with particular emphasis on the use of MoCl as a reactant in vapor phase thin film deposition processes.
本文报道了气相中MoCl、MoOCl和MoOCl在45,500至15,500 cm⁻¹（645至220 nm）范围内的定量吸收光谱。通过快速采样一系列分析物分压，在超高纯不锈钢真空系统中获得光谱。这里采用的短测量时间和差分吸光度法将诸如窗口沉积物等不受控制的瞬态效应降至最低。对重复测量和时间分辨光谱的详细分析表明，120℃下MoCl蒸气的光谱响应通常具有可重复性。基于吸光度-压力曲线分析和光谱峰拟合，确定MoCl蒸气样品中HCl和MoOCl杂质的存在可能性不大。与MoOCl和MoOCl光谱的比较表明，在28,500 cm⁻¹处MoCl具有独特的光谱指纹，这为在可见波长下区分MoCl及其氯氧化物提供了一种便捷方法。还讨论了MoCl在表面的吸附行为，特别强调了MoCl在气相薄膜沉积过程中作为反应物的用途。
