| AVS 54th International Symposium | |
| Thin Film | Friday Sessions |
| Session TF2-FrM |
| Session: | Nanoparticles |
| Presenter: | G.H. Kwon, The University of Alabama |
| Authors: | G.H. Kwon, The University of Alabama T.M. Klein, The University of Alabama W. Hale, AJA International, Inc. G.J. Mankey, The University of Alabama |
| Correspondent: | Click to Email |
Matilda, a nanocluster source, consists of a cluster source, a Retarding Field Analyzer (RFA) and a Magnetic sector. A moveable AJA A310 Series 1"-diameter magnetron sputtering gun enclosed in a water cooled aggregation tube serves as the cluster source. The sputtering pressure in the aggregation tube is controlled in the range of 0.03 - 1 Torr using a mass flow controller. The mean cluster size is found to be a function of gas flow rate, sputtering power, and aggregation length. The kinetic energy distribution of ionized clusters was measured with the RFA. The RFA also serves as a high pass filter which allows only ions having a higher kinetic energy than the cluster charge times the retarding voltage to pass. A silver target was used for initial testing and cluster sizes were measured using a transmission electron microscope. At high Ar flow rates, the mean cluster size is 60 nm and for lower flow, the mean cluster size is reduced to 2 nm. Finer control of cluster size can be achieved using a mixture of He and Ar as the sputtering gas. Our results show the He gas pressure can be optimized to reduce the cluster size variations. The cluster sizes can also be selected using a magnetic sector. The sector is downstream from the RFA, and the magnetic field is applied in a direction perpendicular to the direction of ion motion. The ions are dispersed on a substrate laterally according to size. This new method of fabrication allows the study of size effects on a single substrate to increase throughput. This work was funded by the US DOE under grant number DE-FG02-01ER45867 and shared equipment from NSF-DMR-02-13985.