Field emission image analysis: Precise determination of emission site density and other parameters
2Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
3Nanotech Laboratory, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
Adv. Mater. Lett., 2016, 7 (10), pp 771-776
Publication Date (Web): Aug 01, 2016
Copyright © IAAM-VBRI Press
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.
Field emission, image processing, carbon nanotube.