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Microscopic analysis of performance variations in carbon nanotube field emission cathodes: Implications for device optimization
Author(s) -
Berhanu Sarah,
Gröning Oliver,
Chen Zexiang,
Merikhi Jacqueline,
Kaiser Monja,
Rupesinghe Nalin L.,
Bachmann Peter K.
Publication year - 2012
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201228296
Subject(s) - cathode , field electron emission , materials science , carbon nanotube , common emitter , anode , scanning electron microscope , nanotechnology , contact resistance , transmission electron microscopy , optoelectronics , chemical vapor deposition , electron , composite material , electrode , chemistry , physics , quantum mechanics , layer (electronics)
Carbon nanotubes (CNTs) are considered very promising for the realization of low‐cost field emission electron sources. However, despite intensive research and development efforts, the fabrication of reliable CNT cathodes for high current density (>100 mA/cm 2 ) applications remains a formidable challenge. In this study we use scanning anode field emission microscopy (SAFEM) to investigate the microscopic origins of macroscopic emission performance variations in chemical vapor deposition (CVD) grown CNT planar field emission cathodes. The field enhancement distributions are determined and the field emission properties of individual emission sites on the cathodes are probed. Contact I ( V ) measurements are carried out to estimate the resistance of individual emitters. The degradation behavior of individual sites is also studied and can be related with the macroscopic cathode performances. Scanning (SEM) and transmission electron microscopy (TEM) provide additional information on the contact and structural properties of the cathodes. Our results indicate that the sample macroscopic performances depend strongly on the individual emitter field emission properties in terms of maximum current before degradation and contact resistance.