Wang S, Liang X L, Chen Q, Zhang Z Y, Peng L-M
Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871, China.
J Phys Chem B. 2005 Sep 22;109(37):17361-5. doi: 10.1021/jp053739+.
Field-effect transistors (FETs) have been fabricated using double-walled carbon nanotubes (DWCNTs), and electrical transport measurements have been carried out on 125 DWCNT FETs. Among these devices, 52 were found to show basically semiconducting field-effect characteristics, 44 show metallic characteristics, and 29 show neither pure semiconducting nor metallic characteristics. These 3 distinct types of field-effect characteristics were identified as resulting from the semiconducting (S)-S, metallic (M)-M or M-S, and S-M combinations of the two shells of the DWCNT. While the S-S and M-M or M-S DWCNT devices exhibit similar field-effect characteristics to those by single-walled carbon nanotube (SWCNT) devices, the S-M device responds uniquely to the external gate voltage. In particular, it was found that free charges in the inner metallic shell may screen the outer semiconducting shell from the gate effect and that the screening is directly related to the intershell interaction, which increases with increasing temperature and tube diameter. The screening is disadvantageous to the performance of DWCNT FETs, and a similar effect is expected to occur in MWCNTs.
场效应晶体管（FET）已采用双壁碳纳米管（DWCNT）制造出来，并对125个DWCNT FET进行了电输运测量。在这些器件中，发现52个基本呈现半导体场效应特性，44个呈现金属特性，29个既不呈现纯半导体特性也不呈现金属特性。这三种不同类型的场效应特性被确定为由DWCNT的两个壳层的半导体（S）-S、金属（M）-M或M-S以及S-M组合导致。虽然S-S和M-M或M-S DWCNT器件展现出与单壁碳纳米管（SWCNT）器件类似的场效应特性，但S-M器件对外部栅极电压有独特响应。特别地，发现内部金属壳层中的自由电荷可能使外部半导体壳层免受栅极效应影响，并且这种屏蔽与壳层间相互作用直接相关，壳层间相互作用随温度和管径增加而增强。这种屏蔽对DWCNT FET的性能不利，预计在多壁碳纳米管（MWCNT）中也会出现类似效应。
