Rajkumar Patra; Anjali Singh; V. D. Vankar; S. Ghosh
Abstract
We report a simple and detailed simulation based analysis of an experimental field emission (FE) image captured on a phosphor coated indium tin oxide (ITO)/glass plate due to the electron emission from a multiwalled carbon nanotube (MWCNT) film. Emission intensity versus effective emissive area, number ...
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We report a simple and detailed simulation based analysis of an experimental field emission (FE) image captured on a phosphor coated indium tin oxide (ITO)/glass plate due to the electron emission from a multiwalled carbon nanotube (MWCNT) film. Emission intensity versus effective emissive area, number of CNTs present in the film contributing emission process and number density of MWCNTs at high field (during FE process) along with other FE parameters viz. turn on field, threshold field are determined, which agrees well with experimental results. Over estimation of calculated value over experimental results is realized with creation of new emission sites at high electric field due to combined effect of divergence of electron within electrode because of electron-air molecule collision, assumption of evenly placement of emitters during calculation, damages and/or tear-off of emitters at high electric field, contribution of adsorbates of MWCNT walls and the energy loss due to absorption of phosphor atom. This analysis renders a unique way to analyze field emission data and supports the theoretical formulation to evaluate the best possible values of FE parameters.
Rajkumar Patra; Himani Sharma; Swati Singh; S. Ghosh; V. D. Vankar
Abstract
Designing an efficient field emission source requires theoretical optimization of electron emitters’ geometrical distribution over the surface for its best performance in terms of current density. Seven and nineteen bundles of CNT arrays arranged in different models are analysed in detail using ...
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Designing an efficient field emission source requires theoretical optimization of electron emitters’ geometrical distribution over the surface for its best performance in terms of current density. Seven and nineteen bundles of CNT arrays arranged in different models are analysed in detail using a computational theory in CST studio suite software based on the particle tracking mode. A three dimensional model has been employed to calculate FE properties with high accuracy. Simulations were carried out for a particular number of CNTs of constant height and radius located at fixed distances from each other and arranged in different geometrical patterns. Among all patterns, rectangular arrangement of CNTs is found to produce the maximum current. The edge effect and screening effect are incorporated in calculating total emission current and are found to diminish the contribution of inner rings 10% or less than that of maximum contribution. These findings can be employed as guideline to fabricate pattered CNT structures experimentally for industry applications.