TY - JOUR
T1 - STEM observation of tungsten tips sharpened by field-assisted oxygen etching
AU - Onoda, Jo
AU - Mizuno, Seigi
AU - Ago, Hiroki
N1 - Funding Information:
This work was supported by KAKENHI ( 20340077 ) from the Ministry of Education, Culture, Sports, Science and Technology of Japan and the Industrial Technology Research Grant Program in '05 from NEDO of Japan .
PY - 2010/7/15
Y1 - 2010/7/15
N2 - Tungsten tips oriented toward the <111> direction were fabricated by field-assisted O2 etching, and observed by means of scanning transmission electron microscopy (STEM) and field ion microscopy (FIM). The radii of curvature of the tip apexes were sharpened from 16-20 nm to less than 2 nm. The O2 etching is considered to start from the O2 imaging region depending on the field distribution around the tip apex and shank. We estimated the effect of field distribution derived from a shank shape and applied bias voltage. The results showed that the tip with a cylindrical shank before the O2 etching became sharper than tips having an initial paraboloidal shape, with respective cone angles (defined in Fig. 3) of 58° and 80°. The field emission (FE) patterns of these etched tips became a single spot derived from the W(111) plane, and their opening angles (defined by the full width at half maximum) were 14.4° and 7.8°, respectively.
AB - Tungsten tips oriented toward the <111> direction were fabricated by field-assisted O2 etching, and observed by means of scanning transmission electron microscopy (STEM) and field ion microscopy (FIM). The radii of curvature of the tip apexes were sharpened from 16-20 nm to less than 2 nm. The O2 etching is considered to start from the O2 imaging region depending on the field distribution around the tip apex and shank. We estimated the effect of field distribution derived from a shank shape and applied bias voltage. The results showed that the tip with a cylindrical shank before the O2 etching became sharper than tips having an initial paraboloidal shape, with respective cone angles (defined in Fig. 3) of 58° and 80°. The field emission (FE) patterns of these etched tips became a single spot derived from the W(111) plane, and their opening angles (defined by the full width at half maximum) were 14.4° and 7.8°, respectively.
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U2 - 10.1016/j.susc.2010.03.019
DO - 10.1016/j.susc.2010.03.019
M3 - Article
AN - SCOPUS:77953258395
SN - 0039-6028
VL - 604
SP - 1094
EP - 1099
JO - Surface Science
JF - Surface Science
IS - 13-14
ER -