%0 Journal Article
%T Enhancement of Field Emission Properties of Carbon Nanotubes by ECR-Plasma Treatment
%A Javid Ali
%A Avshish Kumar
%A Samina Husain
%A Shama Parveen
%A Renu Choithrani
%A Mohammad Zulfequar
%A Harsh
%A Mushahid Husain
%J Journal of Nanoscience
%D 2014
%R 10.1155/2014/437895
%X We report a significant improvement in electron field emission property of carbon nanotubes film by using an electron cyclotron resonance plasma treatment. Our research results reveal that plasma treatment can modify the surface morphology and enhance the field emission characteristics of carbon nanotubes. Raman spectra indicate that plasma treated CNTs sample has lesser defects. Before plasma treatment, low current density of 6.5£¿mA/cm2 at 3.0£¿V/¦Ìm and at a high turn-on field of 2.4£¿V/¦Ìm was observed. ECR plasma treated CNTs showed a high current density of 20.0£¿mA/cm2 at 3.0£¿V/¦Ìm and at a low of 1.6£¿V/¦Ìm. The calculated enhancement factors are 694 and 8721 for ECR-plasma untreated and treated carbon nanotubes, respectively. We found an increase in the enhancement factor and emission current after the ECR-plasma treatment. This may be attributed to creation of geometrical features through the removal of amorphous carbon and catalyst particles. 1. Introduction Carbon nanotubes (CNTs) have great attention because of their unique morphologies, which make their uses in wide variety of applications. The different techniques for the synthesis of CNTs have been developed, such as arc discharge method, laser ablation method, and chemical vapor deposition (CVD) [1¨C4]. The most widely used method is CVD technique, in which the synthesis is achieved by putting a carbon source in the gas phase. One of the most promising applications of CNTs is in field emission (FE) devices [5¨C14]. High aspect ratio and atomically sharp radius of apex curvature of the CNTs enhance the local field and lower the threshold field for electron emission. The emission properties of CNTs are governed by the work function, crystalline structure, geometry of their tips, and so forth. In addition, the surrounding gases and impurities on the surface have also been known to strongly affect their FE characteristics. However, the effect of crystallinity of CNTs on the FE has not been much investigated till now. Schwoebel and Spindt [15] experimentally found that low-pressure hydrogen glow discharge can clean the surface contaminants in both microfabricated single molybdenum tips and arrays which resulted in a decrease of ~1£¿eV in the work function. Yu et al. [16] achieved a low-field electron emission in undoped nanostructure diamond by employing a hydrogen plasma heat treatment. Hydrogen plasma has been known to greatly enhance the field emission property of CNTs [17]. These references indicate that plasma treatment is an effective method to improve the field emission property of CNTs. In this
%U http://www.hindawi.com/journals/jns/2014/437895/