Various research fields of CASTECH are listed and introduced in details.
Synthesis of the DMS nanowires
by Jung-Hwan Chun (

1. Motivation
In these days, many researchers change their focus to nanostructures for the expectation of the new science. There are many kinds of nanostructures including CNT (carbon nanotube), nanoparticle, nanowire. These structure represents one-, two- dimensional structures of nanoscience. Among them, DMS (diluted magnetic semiconductor) nanowires are of great interest because of their application in spintronics, which needs the multifunctional use of charge and spin by manipulating them. These DMS nanowires can have the many different kinds of host materials and the dopants. Among them, we focused to ZnO and GaN host materials and Mn, Cr, Co and Bi dopants. With doping this dopants to host materials, we can see the enhanced electrical and magnetical properties.

2. Result

The synthesis of the nanowires is follow the vapor-liquid-solid mechanism and conducted by using a tubular furnace. Figure 1 is schematic diagram of our equipment. Heating and cooling the source with adequate amount of ambient gas, the nanowires can be synthesized. Figure 2 shows the various kinds of nanowires of our group. These nanowires also have magnetic property which was shown in figure 3.

Fig. 1. schematic diagram of apparatus

Fig. 2. The images of nanowires

Fig. 3. The magnetic properties of nanowires

3. Future plan

Until now, our group focused only to synthesize of DMS nanowires. We try to synthesize more better nanowires with the change the dopants and experiments conditions. And besides the nanowires, nanoparticles, especially iron oxide, can be a candidate for a new target for our group.

4. References

1. C. Xu, J. Chun, and D. Kim, B. Chon and T. Joo, ˇ°Structural characterization and low temperature growth of ferromagnetic Bi-Cu codoped ZnO bicrystal nanowiresˇ±, APPLIED PHYSICS LETTERS 97, 153104 (2007)

2. CongKang Xu, Junghwan Chun, Dong Eon Kim, Ju-Jin Kim, Bonghwan Chon, and Taiha Joo, "Electrical properties and near band edge emission of Bi-doped ZnO nanowires", APPLIED PHYSICS LETTERS 90, 083113 (2007)

3. CongKang Xu, Junghwan Chun, Hyo Jin Lee, Yoon Hee Jeong, Seong Eok Han, Ju-Jin Kim, and Dong Eon Kim, "Ferromagnetic and Electrical Characteristics of in Situ Manganese-Doped GaN Nanowires", J. Phys. Chem. C 111, 1180-1185 (2007)

4. CongKang Xu, Junghwan Chun, Bonghwan Chon, Taiha Joo and Dong Eon Kim, "In situ fabrication and blueshifted red emission of GaN:Eu nanoneedles", Nanotechnology 18, 015703 (2007)

Copyright 2012 (c) Center for Attosecond Science and Technology
790-784 dept.Physics, POSTECH, Hyoja-dong, Nam-gu, Pohang, Kyungbuk, South Korea
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