Effect of adsorbates on field emission from carbon nanotubes
Effect of adsorbates on field emission from carbon nanotubes
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DOI：
10.1103/physrevlett.87.155502
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发表时间：
2001-10-08
影响因子：
8.6
通讯作者：
von Allmen, P
中科院分区：
文献类型：
--
作者：
Maiti, A;Andzelm, J;von Allmen, P
最近的实验表明，水分子吸附在碳纳米管尖端显着增强场发射电流。通过第一性原理密度泛函理论的计算，我们发现在零电场下，水与纳米管的相互作用很弱。然而，在发射条件下，管尖端存在大电场：（a）明显增加结合能，从而稳定吸附物;和（B）降低电离电位（IP），从而使其更容易提取电子。通过在纳米管尖端上形成水簇进一步增强IP的降低。
Recent experiments indicate that water molecules adsorbed on carbon nanotube tips significantly enhance field-emission current. Through first-principles density-functional theory calculations we show that the water-nanotube interaction is weak in zero electric field. However, under emission conditions large electric field present at the tube tip: (a) increases the binding energy appreciably, thereby stabilizing the adsorbate; and (b) lowers the ionization potential (IP), thereby making it easier to extract electrons. Lowering of IP is enhanced further through the formation of a water cluster on the nanotube tip.