镍改性层增强铜基底沉积金刚石膜的形核

摘要

在铜基底溅射约100 nm厚的镍改性层,然后置入纳米金刚石悬浮液中超声震荡加载籽晶,随后在热丝化学气相沉积设备中制备出晶体颗粒接近热力学平衡形态的高质量金刚石膜,其中sp2碳相含量低于5.56％.分别采用激光拉曼光谱、扫描电镜与X射线衍射对金刚石膜的形核与生长进行研究.实验结果表明:在溅射有镍改性层的铜基底上,金刚石的形核密度比在无改性层的铜基底上的形核密度高10倍.镍改性层的增强机制主要来源于两个方面:镍改性层的纳米级粗糙表面增强金刚石籽晶颗粒的吸附；镍改性层的强催化效应加速铜基底上金刚石形核生长所需的石墨过渡层的形成,从而促进金刚石的快速形核.%A Ni layer with a thickness of about 100 nm was sputtered on Cu substrates,followed by an ultrasonic seeding with nanodiamond suspension.High-quality diamond film with its crystalline grains close to thermal equilibrium shape was deposited on Cu substrates by hot-filament chemical vapor deposition (HF-CVD),and the sp2 carbon content was less than 5.56％.The nucleation and growth of diamond film were investigated by micro-Raman spectroscopy,scanning electron microscopy,and X-ray diffraction.The results show that the nucleation density of diamond on the Ni-modified Cu substrates is 10 times higher than that on blank Cu substrates.The enhancement mechanism of the nucleation kinetics by Ni modification layer results from two effects:namely,the nanometer rough Ni-modified surface shows an improved absorption of nanodiamond particles that act as starting points for the diamond nucleation during HF-CVD process; the strong catalytic effect of the Ni-modified surface causes the formation of graphite layer that acts as an intermediate to facilitate diamond nucleation quickly.