Among the three main methods for the s ynthesis of carbon nanotubes(CNTs ),chemical vapor deposition(CVD)has received a great deal of attentio n since CNTs can be synthesized at sig nificantly low temperature.Plasma c...Among the three main methods for the s ynthesis of carbon nanotubes(CNTs ),chemical vapor deposition(CVD)has received a great deal of attentio n since CNTs can be synthesized at sig nificantly low temperature.Plasma chemical vapor deposition me thods can synthesize CNTs at lower te mperature than thermal CVD.But in th e usual catalytic growth of CNTs by CVD,CNTs are often tangled together and have some defects.These will limit t he property research and potential applications.How to synthesize the str aight CNTs at low temperature become s a challenging issue.In this letter,s traight carbon nanotube(CNT)films were achieved by microwave pla sma chemical vapor deposition(MWPCVD)catalyzed by round Fe-Co-Ni alloy particles on Ni substrate at 610℃.It wa s found that,in our experimental condition,the uniform growth rate along the circumference of round alloy particles plays a very important role in the gro wth of straight CNT films.And because the substrate is conducting,the straight CNT films grown at low temperature ma y have the benefit for property research and offer the possibility to use t hem in the future applications.展开更多
Well aligned nanotubes with diameter of 30—50 nm have been synthesized on a porous alumina template by microwave plasma enhanced chemical vapor deposition (MW PECVD). By this means, the control over either diameter o...Well aligned nanotubes with diameter of 30—50 nm have been synthesized on a porous alumina template by microwave plasma enhanced chemical vapor deposition (MW PECVD). By this means, the control over either diameter or length of the nanotubes could be realized. The hollow structure and vertically aligned features have been verified by scanning electron and transmission electron microscopic images. In comparison with the reported fabrication methods, lower synthesis temperature (below 520 ℃) and simpler process (no negative dc bias applied) have been achieved, which could be of great importance for both theoretical research and pratical applications.展开更多
类金刚石薄膜由于其独特的物理化学特性,使得该薄膜在光学、电学、机械、医学、航空航天等领域得到了广泛应用。等离子体增强化学气相沉积(plasma enhanced chemical vapor deposition,PECVD)制备类金刚石是近几十年兴起的新的制备类金...类金刚石薄膜由于其独特的物理化学特性,使得该薄膜在光学、电学、机械、医学、航空航天等领域得到了广泛应用。等离子体增强化学气相沉积(plasma enhanced chemical vapor deposition,PECVD)制备类金刚石是近几十年兴起的新的制备类金刚石薄膜的方法,因其对沉积温度要求低,对基底友好,同时还具有沉积速率快和无转移生长的优势,获得了越来越多的研究者关注。详细介绍了类金刚石薄膜优异的特性,阐述了在等离子化学气相沉积条件下,不同沉积条件对沉积类金刚石薄膜结构特性的影响。衬底的选择直接影响着沉积类金刚石薄膜的性能,不同的衬底直接决定着生成类金刚石结构中sp^(3)相的数量和质量;沉积参数是最为常见的控制条件,对沉积薄膜的总体效果影响也是最大的,改变沉积参数,沉积薄膜的表面将会变得更加光滑致密;常用的掺杂元素是硅和氮,掺杂元素的引入往往是为了降低沉积薄膜的内应力,提高与衬底间的结合力,延长使用寿命等;由于很难直接在金属上沉积类金刚石薄膜,所以常通过制备复合层来改善沉积效果。最后对类金刚石薄膜的发展以及今后研究方向进行了展望。展开更多
文摘Among the three main methods for the s ynthesis of carbon nanotubes(CNTs ),chemical vapor deposition(CVD)has received a great deal of attentio n since CNTs can be synthesized at sig nificantly low temperature.Plasma chemical vapor deposition me thods can synthesize CNTs at lower te mperature than thermal CVD.But in th e usual catalytic growth of CNTs by CVD,CNTs are often tangled together and have some defects.These will limit t he property research and potential applications.How to synthesize the str aight CNTs at low temperature become s a challenging issue.In this letter,s traight carbon nanotube(CNT)films were achieved by microwave pla sma chemical vapor deposition(MWPCVD)catalyzed by round Fe-Co-Ni alloy particles on Ni substrate at 610℃.It wa s found that,in our experimental condition,the uniform growth rate along the circumference of round alloy particles plays a very important role in the gro wth of straight CNT films.And because the substrate is conducting,the straight CNT films grown at low temperature ma y have the benefit for property research and offer the possibility to use t hem in the future applications.
文摘Well aligned nanotubes with diameter of 30—50 nm have been synthesized on a porous alumina template by microwave plasma enhanced chemical vapor deposition (MW PECVD). By this means, the control over either diameter or length of the nanotubes could be realized. The hollow structure and vertically aligned features have been verified by scanning electron and transmission electron microscopic images. In comparison with the reported fabrication methods, lower synthesis temperature (below 520 ℃) and simpler process (no negative dc bias applied) have been achieved, which could be of great importance for both theoretical research and pratical applications.
文摘类金刚石薄膜由于其独特的物理化学特性,使得该薄膜在光学、电学、机械、医学、航空航天等领域得到了广泛应用。等离子体增强化学气相沉积(plasma enhanced chemical vapor deposition,PECVD)制备类金刚石是近几十年兴起的新的制备类金刚石薄膜的方法,因其对沉积温度要求低,对基底友好,同时还具有沉积速率快和无转移生长的优势,获得了越来越多的研究者关注。详细介绍了类金刚石薄膜优异的特性,阐述了在等离子化学气相沉积条件下,不同沉积条件对沉积类金刚石薄膜结构特性的影响。衬底的选择直接影响着沉积类金刚石薄膜的性能,不同的衬底直接决定着生成类金刚石结构中sp^(3)相的数量和质量;沉积参数是最为常见的控制条件,对沉积薄膜的总体效果影响也是最大的,改变沉积参数,沉积薄膜的表面将会变得更加光滑致密;常用的掺杂元素是硅和氮,掺杂元素的引入往往是为了降低沉积薄膜的内应力,提高与衬底间的结合力,延长使用寿命等;由于很难直接在金属上沉积类金刚石薄膜,所以常通过制备复合层来改善沉积效果。最后对类金刚石薄膜的发展以及今后研究方向进行了展望。
