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The imaging mechanism of single‐walled carbon nanotubes on Si/SiO 2 wafer in scanning electron microscopy
Author(s) -
ZHANG LIJIE,
GAO FENGLEI,
HUANG SHAOMING
Publication year - 2011
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2010.03422.x
Subject(s) - carbon nanotube , wafer , materials science , magnification , scanning electron microscope , secondary electrons , acceleration voltage , beam (structure) , cathode ray , substrate (aquarium) , optoelectronics , electron , electric field , optics , nanotechnology , physics , composite material , oceanography , quantum mechanics , geology
Summary Scanning electron microscopy imaging of both suspended single‐walled carbon nanotubes (SWNTs) and contacted SWNTs with Si/SiO 2 substrate has been studied in this paper. The voltage contrast has been investigated by supplying external electric field around the samples. The results show that the image contrast of SWNTs attributes to both voltage contrast from the area surrounding SWNTs (tens of nanometres in both sides of the SWNTs) and electron beam induced emission from SWNTs themselves under low primary beam energy. Under high primary beam energy, however, EBIE dominates the image contrast due to the fact that the voltage contrast caused by implanted charges of the SiO 2 layer is weakened. Imaging under the primary beam energy lower than 1 keV offers widened diameter of SWNTs, which promises that the SWNTs are observable at very low magnification (lower than 100×). At a larger magnification, however, imaging under the primary beam energy higher than 10 keV can display more realistic images of the SWNTs. In addition, an appropriate external electric field can improve the images.