1. 1 Directed Electrochemical Nanowire Assembly SRINIVASA REDDY Department of Physics Oklahoma State University

2. 2 Introduction A critical issue in nanoscience is the conduction through very thin metallic wires. As the wire diameter decreases the mean free path for conduction electrons decreases, leading to the inelastic collision of the electrons with the boundary surfaces of the metal. Experimental verification of this issue is ambiguous and requires the fabrication of diameter-tunable, single-crystal, metallic nanowires with low contact resistance interfacing in the external circuitry.

3. 3 Directed Electrochemical Nanowire Assembly (DENA) Palladium wires from palladium acetate solution.* Developed DENA technique**: Single-step growth and interfacing of (near) single-crystalline metallic nanowires from simple salt solutions. *C. Cheng, R.K.G., Q. Gu, and D. T. Haynie, Nano Letters, 5, 175, 2005 **I. Talukdar, B. Ozturk, T.D. Mishima, B.N. Flanders, Appl. Phys. Lett., 88, 221907 (2006) **B. Ozturk, D.R. Grischkowsky, T.D. Mishima and B.N. Flanders, Nanotechnology, 18, 175707 (2007) 20  m

4. 4 Structural variation of indium wires Control of the growth voltage and solution concentration gives rise to structural variation: (b) amorphous, (c) dendritic, (d) needle. I. Talukdar, B. Ozturk, T.D. Mishima, B.N. Flanders, Appl. Phys. Lett., 88, 221907. (2006) 20  m

5. 5 1  m 0.5 MHz 1.0 MHz3.5 MHz Frequency dependent diameter SEM micrographs of indium wires grown with increasing growth frequency. I. Talukdar, B. Ozturk, B. N. Flanders, In preparation. (2007)

6. 6 As the growth frequency increases, the wire diameter decreases. Frequency dependent diameter

7. 7 Wire growth velocity increases with increasing frequency. Velocity and diameter are anti-correlated: signature of dendritic growth.* Frequency dependent velocity * G. P. Ivantsov, Dokl. Akad. Nauk. SSSR 58, 567 (1947) J. S. Langer and H. Muller-Krumbhaar, Acta. Metall. 26, 1961 (1978)

8. 8 Conclusions DENA technique allows the single-step growth and interfacing of crystalline, metallic submicron wires from simply prepared solutions. Wire diameter is tunable down to ~ 100 nm with the control of the growth frequency. These capabilities will facilitate future studies of diameter-dependent transport measurements with the DENA technique. We applied DENA technique to the growth of In, Ni, Au, Co, Cu, Ag, Zn and Pb wires.

9. 9 Acknowledgements Dr. Bret N. Flanders Dr. Birol Ozturk Prem Thapa FUNDING NER-304413 EPS-132354 ECS-0601362

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