Influence of ion energy and substrate temperature on the optical and electronic properties of tetrahedral amorphous carbon (ta-C) films
Influence of ion energy and substrate temperature on the optical and electronic properties of tetrahedral amorphous carbon (ta-C) films
复制标题
DOI：
10.1063/1.364000
复制
发表时间：
1997-01-01
影响因子：
3.2
通讯作者：
Milne, WI
中科院分区：
文献类型：
--
作者：
Chhowalla, M;Robertson, J;Milne, WI
本文报道了用过滤阴极真空沉积的无定形碳（a-C）的性质与离子能量和衬底温度的关系。发现sp（3）分数强烈地依赖于离子能量，在约100 eV的离子能量下给出高度sp（3）键合的a-C，表示为四面体无定形碳（ta-C）。发现光学带隙遵循类似的趋势，其他类金刚石碳膜，几乎线性变化的sp（2）分数。根据a-C的电子结构模型讨论了电子性质的依赖关系。ta-C的结构也强烈依赖于沉积温度，在转变温度T-1（约200 ℃）以上急剧变化为sp（2）。此外，T-1被发现随着离子能量的增加而降低。大多数膜的性质，如压缩应力和等离子体激元能量，与sp（3）分数。然而，光学和电学性质被发现经历一个更渐进的过渡与沉积温度，我们归因于中程秩序的sp（2）网站。我们属性的变化与沉积温度的薄膜性质的扩散的金属到表面以上的T-1由于热激活，导致密度的松弛的背景下的生长模型。(C)1997年美国物理学会。
The properties of amorphous carbon (a-C) deposited using a filtered cathodic vacuum are as a function of the ion energy and substrate temperature are reported. The sp(3) fraction was found to strongly depend on the ion energy, giving a highly sp(3) bonded a-C denoted as tetrahedral amorphous carbon (ta-C) at ion energies around 100 eV. The optical band gap was found to follow similar trends to other diamondlike carbon films, varying almost linearly with sp(2) fraction. The dependence of the electronic properties are discussed in terms of models of the electronic structure of a-C. The structure of ta-C was also strongly dependent on the deposition temperature, changing sharply to sp(2) above a transition temperature, T-1, of approximate to 200 degrees C. Furthermore, T-1 was found to decrease with increasing ion energy. Most film properties, such as compressive stress and plasmon energy, were correlated to the sp(3) fraction. However, the optical and electrical properties were found to undergo a more gradual transition with the deposition temperature which we attribute to the medium range order of sp(2) sites. We attribute the variation in film properties with the deposition temperature to diffusion of interstitials to the surface above T-1 due to thermal activation, leading to the relaxation of density in context of a growth model. (C) 1997 American Institute of Physics.