ABSTRACT
Metal nanoclusters were fabricated by inert-gas condensation in a sputtering reactor. From transmission electron microscopy, it was confirmed that copper nanoclusters with a high degree of monodispersity in size of about 5 nm were successfully produced. The conductance of the percolated nanocluster film was measured. In order to incorporate nano-scale arrangement characterizations in nano-devices being operated in air, aging experiments of the specimen after long time in air were carried. Negative temperature coefficient of resistance suggests that surface native copper oxide in core-shell structured nanoclusters was mainly responsible for the conductance, because copper oxide is known as semiconductor. After aged at higher than 100 degrees C, the conductance at room temperature didn't return to the original value. This irreversible phenomenon might be due to coarsening and/or coalescence of copper nanoclusters.
ABSTRACT
The visualization of two-dimensional dopant profiles and the quantitative analysis of the built-in potential across the p-n junction, DeltaV(p-n), by electron holography were carried out with specimens prepared from the backside ion milling method combined with the focused ion beam technique. It was possible to obtain dopant profiling of the large field of view with low surface damage and gradually changed thickness. From the quantitative analysis using the phase information of electron holography and the thickness information of electron energy-loss spectroscopy, DeltaV(p-n) was estimated to be about 0.78 V assuming that the thickness of the dead layer on both surfaces is 50 nm, which is to show the difference of within 12% from the calculated value. It demonstrates that the backside ion milling method is a very promising specimen preparation technique for the reliable and quantitative analysis of dopant profiling with electron holography.
