International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

AP/AM-04

MeV Ion Beam Assisted Formation of Pseudo-Crystals

D. Ila, R.L. Zimmerman, and C. Muntele

Center for Irradiation of Materials, Alabama A&M University, Normal, United States of America

Corresponding Author: ila@aamuri.aamu.edu

For the past fifteen years, we have formed nanostructure in the MeV ion beam track in order to fabricate pseudo-crystals consisting of nanostructures. The focus of our work is based on the energy deposited due to ionization in order to produce quantum dots or nano-structures resulting to production of pseudo-crystal consisting of nano-crystals with applications in optical devices as well as with applications in highly efficient thermoelectric Materials. The interacting nanocrystals enhance the electrical conductivity, reduce thermal conductivity and increase the Seebeck coefficient, in order to produce highly efficient thermoelectric materials. Theoretically, the regimented quantum dot superlattice/pseudo-crystals consisting of nanostructures of any materials produces new physical properties such as new electrical band structure, phonon mini-bands, as well as improved mechanical. A proper choice of nanocrystals, host and buffer layer result in production of highly efficient thermoelectric generator (TEG)* with efficiencies as high as 30% which correspond to figure of merit above 4.0. In addition to above such systems are in a unique position to be used both as electrical generation from heat and/or other forms of radiation as well as cooling the structures, thus enhance the applicability of hybrid systems.
The interaction of nanostructures results in phonon mini-bands formation reducing the thermal conductivity, while increasing the electrical conductivity resulted in synthesis of TEG with much higher efficiency than reported to this date. We will review a series of materials selected for investigation some operating at temperatures around 300K and some at about 1000K. Sponsors: Supported in part by the Center for Irradiation of Materials, Alabama A&M University and by the AAMURI Center for Advanced PropulsionMaterials under the contract number NAG8- 1933 from NASA, and by National Science Foundation under Grant No. EPS–0814103.

* Patent filed/Patent Pending.