Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268

Mon., April 27, 2009, at 3:00 p.m. (refreshments at 2:40 p.m.)

Simulated Experiments of Particle and Plasma-Surface Interactions at the Nanoscale

Jean Paul Allain, Purdue University, West Lafayette, IN
Building 6008 Conference Room

The modification of heterogeneous surfaces during particle and plasma irradiation requires an understanding of elemental, chemical and structural evolution at the nanoscale. This is particularly important for systems exposed to high-intensity low-energy irradiation such as plasma-facing components in fusion energy experimental nuclear reactors and plasma-facing mirrors used in nanolithography. In extreme UV lithography sources hyperthermal (50-1000 eV) Sn ions are an ultra-shallow implant in Ru thin-film mirrors penetrating a few nanometers and subsequently diffusing to sublayers below the air/film interface. The implanted species directly affect the EUV optical reflective properties of the mirror at wavelengths that approach the implantation zone. This is particularly important in advanced microlithography applications.

Prof. Allainís group designed and built the IMPACT (Interaction of Materials with Particles and Components Testing) experimental facility designed to study In-situ nanoscale characterization of particle-induced growth and synthesis of surface or low-dimensional state systems tailored during energetic or thermal particle exposure. Surface-sensitive techniques include: low-energy ion scattering spectroscopy (LEISS), direct recoil spectroscopy (to study hydrogen levels in nanostructures), X-ray photoelectron spectroscopy (XPS) and in-situ sputtering erosion monitoring. This talk will focus on the limits and challenges that face in-situ characterization studies of thin-film or low-dimensional state systems during irradiation. The talk will also highlight a new experimental facility being built at Purdue known as PRIHSM (Particle and Radiation Interaction with Soft and Hard Matter). PRIHSM includes: UPS (ultraviolet photoelectron spectroscopy), LEISS (low-energy ion scattering spectroscopy) and ARPES (angular-resolved photoelectron spectroscopy) materials characterization during energetic particle (ion-beam) and gas interaction with candidate materials. LEISS measures elemental mapping of surface structure, UPS measures valence shell dynamics and ARPES maps the energy-momentum electronic band structure. PRIHSM at Purdue will provide a unique opportunity to directly link structure, bonding and electronic configuration with materials performance under a variety of irradiation and thermal regimes. In particular, establishing radiation directed synthesis of a variety of materials (metals, semiconductors, semi-metals, ceramic compounds, etc.) for nanostructure templating and manipulation.

NOTE: Date of Seminar has changed.