J.P. Allain^1,2

¹Purdue University, West Lafayette, IN 47907

²Birck Nanotechnology Center, Discovery Park, West Lafayette, IN 47907

The Radiation Surface Science and Engineering Laboratory (RSSEL) group headed by Prof. Allain focuses on deciphering self-organized mechanisms of nanostructures across multiple spatio-temporal scales.  Our group studies damage at the plasma-material interface in burning plasma fusion environments but also how to take advantage of radiation-induced modification to tailor new metastable phases with new properties in materials.  This talk is divided in two parts: 1) An overview of plasma-material interactions and research in fusion materials science and 2) A short summary of irradition-driven synthesis of various nanostructured materials and their general applications.

The plasma-material interface and its impact on performance of magnetically-confined thermonuclear fusion plasma is considered to be one of the key scientific gaps in the realization of nuclear fusion power.  At this interface high particle and heat flux from the fusion plasma can limit the material’s lifetime and reliability and therefore hinder operation of the fusion device.  The power dissipated over the plasma-wetted surfaces can lead to substantial degradation of materials.  In particular, when operating in burning plasma, long-pulse regimes the plasma-facing components are exposed to large fluxes of helium compromising candidate materials, which include tungsten, graphite and beryllium.

Ion-driven nanostructures (e.g. nanodots, ripples) on compound semiconductors and silicon via low-energy ion beam irradiation is critical to manipulate functionality in nanostructured systems. By operating at ultra-low energies near the damage threshold, irradiation-driven defect engineering can be optimized (e.g. 10-500 eV).  Tunability of optical, electronic, magnetic and nuclear detection properties is realized by reaching metastable phases controlled by irradiation.  This talk summarizes emerging research that exploits irradiation-driven materials modification with applications in: nanophotonics, nanoelectronics, biomaterials and nuclear detection.  Furthermore advances of in-situ analysis conducted during modification to correlate tunable irradiation synthesis and device performance will be summarized.