Structural analysis of nanometer-size pyramid grown on an end of tungsten blunt tip

We have fabricated nanometer-size pyramids (nanopyramids) on blunt W tips to apply for bright field emitter. The blunt tips were preliminarily given remolding treatment in order to sharpen their ends. The nanopyramids were grown on the tip end by being covered with thin layers of Pd and subsequently annealed at 1000 K. The structures of the specimen were analyzed by using filed ion microscopy (FIM). As a result, we have clarified detailed information about the atomic structures, of which the acquisition was not allowed in case that only FEM was employed. As far as the remolded W tips were concerned, the tip-end dimension of about 3 nm was narrowest possible for all the combinations of the remolding temperature and electric field. On the other hand, the grown nanopyramid with {211} sides and monoatomic-chain ridges exhibited even narrower summit. These findings are consistent with the contrasting behaviors of current stability data previously clarified by the FEM study.