[2P01-53] Poster Presentation

[2P18] Atom probe study of tungsten nano-tips fablicated by field-assisted oxygen etching with fixed and decreasing bias methods

*Ikumi Kuroda¹, Masanori Nanjo¹, Tatsuo Iwata¹, Shigekazu Nagai¹ (1. Graduate school of engineering, Mie university)

To improve characteristics of field emitters, methods to fabricate nano-tips have been investigated. One of these methods is field-assisted oxygen etching. The final shape of the tip can be controlled by two methods which are the decreasing bias method for extreme sharp tip and the fixed bias method to form a nano-protrusion. It has been reported that the tips fabricated by the decreasing bias method enable to extract the electron beam by applying only 4 V, which is speculated that the results relate to composition of the tip apex. We analyze the composition of tips fabricated by fixed and decreasing bias methods by using an atom probe. Only pure tungsten detected for the tip fabricated by the decreasing bias method, and pure tungsten and tungsten oxide were detected alternately for the tip fabricated by the fixed bias method. The difference is attributed to final form of the tip. In conclusion, the extremely low bias electron emission is not attributed to composition of the tip apex.