硼/氮共掺杂使金属性单壁碳纳米管转变成半导体

Converting Metallic Single-walled Carbon Nanotubes into Semiconductors by Boron/Nitrogen Co-doping

本研究小组利用硼和氮共掺杂碳纳米管构筑了大量的场效应晶体管,并对其电学性质进行了统计分析研究。结果表明,通过对单壁碳纳米管进行硼和氮共掺杂,样品中半导体性纳米管的比例由67%提升到高于97%。为了深入理解这一重要实验发现,我们利用第一性原理,计算了掺杂对单壁碳纳米管能带结构的调制作用。结果证明,硼和氮共掺杂可使金属性单壁碳纳米管的能隙被打开,转变为半导体性纳米管,但并不改变半导体性碳纳米管的导电属性,从而在理论上解释了硼和氮共掺杂调节碳纳米管能带结构的物理机制。这项工作为纳米管电子和光电子器件走向实际应用提供了一条新途径。

Coexistence of metallic and semiconducting singlewalled carbon nanotubes （C-SWNTs） in as-grown materials has made it notoriously difficult to scale up fabrication of carbon nanotube field effect transistors （FETs）. Here we showed that boron-nitrogen （B-N） co-doped C-SWNTs （BCN-SWNTs） provide a solution to this long standing problem. We finded that more than 97% of the synthesized BCN-SWNTs were semiconductors, while undoped C-SWNTs consist of only about 67% semiconductors. Ab initio calculations reveal that the BN co-doping into C-SWNTs at an atomic concentration of - 5% can change a metallic C-SWNT to a semiconduting BCN-SWNT with a moderate band gap useful for FETs, consistent with experimental results. Purely semiconducting BCN-SWNTs are thus promising materials for the fabrication and assembly of electronic devices on a large scale.