缓冲层对铜催化生长碳管形貌和性能的影响

摘要

Copper is a good catalyst besides Fe, Co, Ni for carbon nanotubes (CNTs) growth in field emis-sion display application, because the emission properties of as-grown CNTs on glass substrate afford low threshold field, high current density, and uniformity. Growing carbon nanotubes on glass substrate sur-face requires the formation of high-density catalyst nanoparticles. This, in turn, requires the minimum dif-fusion of catalyst into the substrate at the growth temperature for carbon nanotubes. Four metals (W, Ni,Cr and Ti) as the diffusion barrier have been optimized and examined for growing carbon nanotubes on glass substrate. The bilayer films were annealed at 550℃ in hydrogen gas for few minutes to form nanop-articles to grow CNTs under the atmosphere of C2H2/H2 by chemical vapor deposition (CVD) method.With an optimized barrier layer (Ti, or W), carbon nanotubes with excellent adhesion to the substrate and good field emission properties have also been achieved.%碳纳米管的生长通常使用Fe,Co,Ni作为催化剂,除此以外的一些过渡元素也能催化裂解生长碳管.其中用铜制备的碳管阈值电场低、发射电流密度大、发射均匀性好等等良好的场发射特性.铜与硅、或金属之间具有很强的的扩散特性,而碳管应用于场发射显示器必然使用玻璃、硅片作为衬底,所以需要一层缓冲层阻挡催化剂铜扩散入衬底.本文使用磁控溅射制备铜薄膜作为催化剂,化学气相沉积方法裂解乙炔生长碳管薄膜形成场发射阴极.并试验 W,Ni,Cr 和 Ti 作为铜薄膜的缓冲层,结果表明不同的金属阻挡特性不同,生长后碳管的形貌和特性都有差异.结果表明 Ti 和 W 能很好地阻挡铜的扩散,从而使铜催化裂解出附着性好、分布均匀、密度适中、场发射特性良好的碳管薄膜.对于 Ni 和 Cr 金属,由于生长的碳管与衬底结合差或者场发射能力差而不适合作铜的缓冲层.