Patterson J R, Vohra Y K, Weir S T, Akella J
Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294-1170, USA.
J Nanosci Nanotechnol. 2001 Jun;1(2):143-7. doi: 10.1166/jnn.2001.026.
Single-wall carbon nanotube samples were studied under high pressures to 62 GPa using designer diamond anvils with buried electrical microprobes that allowed for monitoring of the four-probe electrical resistance at elevated pressure. After initial densification, the electrical resistance shows a steady increase from 3 to 42 GPa, followed by a sharp rise above 42 GPa. This sharp rise in electrical resistance at high pressures is attributed to opening of an energy band gap with compression. Nanoindentation hardness measurements on the pressure-treated carbon nanotube samples gave a hardness value of 0.50 +/- 0.03 GPa. This hardness value is approximately 2 orders of magnitude lower than the amorphous carbon phase produced in fullerenes under similar conditions. Therefore, the pressure treatment of single-wall carbon nanotubes to 62 GPa did not produce a superhard carbon phase.
使用带有嵌入式电微探针的特制金刚石砧座，对单壁碳纳米管样品在高达62吉帕的高压下进行了研究，该探针能够在高压下监测四探针电阻。在初始致密化之后，电阻从3吉帕到42吉帕呈现稳定增加，随后在42吉帕以上急剧上升。高压下电阻的这种急剧上升归因于随着压缩出现了能带隙。对经过压力处理的碳纳米管样品进行的纳米压痕硬度测量得出硬度值为0.50±0.03吉帕。该硬度值比在类似条件下富勒烯中产生的非晶碳相低约2个数量级。因此，将单壁碳纳米管压力处理至62吉帕并未产生超硬碳相。
