David D. Allred received Alumni Professorship Award

Abstract: The plastic substrates, reflective layers, dyes, and adhesives of four archival-grade, recordable DVDs and one standard-grade recordable DVD were analyzed to determine their chemical compositions and/or physical dimensions. Chemical analyses by attenuated total internal reflection Fourier transform infrared spectroscopy, time-of-flight secondary ion mass spectrometry, x-ray photoelectron spectroscopy, energy-dispersive x-ray/scanning transmission electron microscopy, and Rutherford backscattering spectrometry show that all these DVDs use very similar polycarbonate plastic substrates and acrylate-based adhesives, but different reflective layers and dye write layers. In addition, physical measurements by atomic force microscopy show differences in the DVD groove depth, width, and other dimensions. These chemical and physical analyses may help explain variations in DVD lifetimes and facilitate development of the next-generation archival-grade DVDs. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3529981]

Abstract: Dilute magnetic semiconductors based on transition metal doped silicon have attracted intense interest in recent years due to their compatibility with current silicon technology. Here we present transmission electron microscopy, secondary ion mass spectrometry and ferromagnetic resonance studies of silicon implanted with 1×1016 ions/cm2 of Mn ions and silicon co-implanted with both 1×1016 ions/cm2 of Mn ions and 2×1016 ions/cm2 of carbon ions at a substrate temperature of 350 °C. Afterward, the samples were annealed at temperatures between 800 and 1000°C. The SIMS results show a marked difference between the two specimens while the TEM results show similar features in terms of Mn precipitation and particle evolution. The carbon implanted specimens show additional features that appear to be amorphous silicon pockets within the crystalline implant region. Only one specimen (Mn only implant, unannealed) showed any ferromagnetic properties.

Abstract: The structural and magnetic properties of similar to 12 nm thick FePt thin films grown on Si substrates annealed using a 1064 nm wavelength laser with a 10 ms pulse have been examined. The A1 to L1(0) ordering phase transformation was confirmed by electron and X-ray diffraction. An order parameter near 50% and a maximum coercivity of 12 kOe were obtained with laser energy densities of 25-32 J/cm(2). Grain growth, quantified by dark field transmission electron microscopy, occurred during chemical ordering at the laser pulse widths studied. Published by Elsevier B.V.

Abstract: A highly durable optical disk has been developed for data archiving. This optical disk uses tellurium as the write layer and carbon as a dielectric and oxidation prevention layer. The sandwich style CTeC film was deposited on polycarbonate and silicon substrates by plasma sputtering. These films were then characterized with AFM, SEM, TEM, EELS, and ellipsometry and were tested for writability and longevity. Results show the films were uniform in physical structure, stable, and able to form permanent pits. Data was written to a disk and successfully read back in a commercial DVD drive.

Abstract:

Abstract: The plastic substrates, reflective layers, dyes, and adhesives of four archival-grade DVDs and one standard-grade recordable DVD were analyzed to determine their chemical compositions and/or physical dimensions. Chemical analyses by ATR-FTIR, ToF-SIMS, XPS and EDX/STEM show that all these DVDs use very similar polycarbonate plastic substrates and acrylate-based adhesives, but different reflective layers and dye write layers. In addition, physical measurements by AFM show differences in the DVD groove depth, width, and other dimensions. These chemical and physical analyses may help explain variations in DVD lifetimes and facilitate development of the next generation of archival-grade DVDs.