Abstract Amorphous carbon thin films were prepared by direct current hollow cathode sputter deposition in Ar discharge with the injection of small amounts of H2 and/or N2. The influence of these additives on the film properties with particular focus on the application as a coating for electron cloud mitigation in particle accelerators is characterized by optical spectroscopy, X-ray photoelectron spectroscopy, and secondary electron yield (SEY) measurements. The SEY maximum increased from initially 0.98 with pure Ar in the gas discharge up to 1.38 at 0.5% H2 while the addition of 1% of pure N2 enabled to reduce it to 0.88. The simultaneous addition of N2 to the H2 containing discharge allowed an average SEY maximum reduction of 20%. The optical bandgap revealed a correlation between the increase/decrease of the bandgap and the SEY increment/reduction for H2/N2 addition. The surface composition changes and the resulting modification of the sp2/sp3 ratio correlate with the changes in SEY and optical properties. The obtained results highlight the potential of intentionally injected N2 to counteract the detrimental effect of the inevitable H2 partial pressure in the coating systems during the production of amorphous carbon thin films for anti-multipacting applications in particle accelerators.

中文翻译：

---

H2 和 N2 对用于防多重应用的溅射非晶碳薄膜的材料性能和二次电子产率的影响

摘要 通过注入少量H2和/或N2的Ar放电直流空心阴极溅射沉积制备非晶碳薄膜。这些添加剂对薄膜性能的影响，特别是作为粒子加速器中电子云减缓涂层的应用，其特征在于光谱、X 射线光电子能谱和二次电子产率 (SEY) 测量。SEY 最大值从气体放电中纯 Ar 的最初 0.98 增加到 0.5% H2 时的 1.38，而添加 1% 的纯 N2 能够将其降低到 0.88。同时向含 H2 的排放物中加入 N2 可使 SEY 平均最大减少 20%。光学带隙揭示了带隙的增加/减少与 H2/N2 添加的 SEY 增加/减少之间的相关性。表面组成的变化以及由此产生的 sp2/sp3 比率的变化与 SEY 和光学性质的变化相关。获得的结果强调了有意注入 N2 的潜力，以抵消在生产无定形碳薄膜期间涂层系统中不可避免的 H2 分压的不利影响，用于粒子加速器中的抗多重作用应用。