Silicon Chemical Vapor Infiltration

Here, the authors report the fabrication of transparent polymer templates for nanostructured amorphous siliconphotovoltaics using low-cost nanoimprint lithography of polydimethylsiloxane. The template contains a square two-dimensional array of high-aspect-ratio nanoholes (300 nm diameter by 1 μm deep holes) on a 500×500 nm2 pitch. A 100 nm thick layer of a-Si:H was deposited on the template surface resulting in a periodically nanostructured film. The optical characterization of the nanopatterned film showed lower light transmission at 600–850 nm wavelengths and lower light reflection at 400–650 nm wavelengths, resulting in 20% higher optical absorbance at AM 1.5 spectral irradiance versus a nonpatterned film.

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]

Covalently bonded monolayers of two monofunctional aminosilanes (3-aminopropyldimethylethoxysilane. APDMES, and 3-aminopropyldiisopropylethoxysilane, APDIPES) and one trifunctional aminosilane (3-aminopropyltriethoxysilane, APTES) have been deposited on dehydrated silicon subsumes by chemical vapor deposition (CVD) at 150 C and low pressure (a few Torr) using reproducible equipment Standard surface analytical techniques such as x-ray photoelectron spectroscopy (XPS). contact angle gontometry, spectroscopic ellipsometry. atomic force microscopy, and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) have been employed to characterize the resulting Films These methods indicate that essentially constant surface coverages arc obtained over a wide range of gas phase concentrations of the aminosilanes XPS data further indicate that the NIs/Si2p ratio is Iliac! after CVD with the trifunctional Wane (APTES) compared to the monofunctional ones, with a higher NIs/Si2p ratio lot APDMES compared to that for APDIPES A FM images show an average surface roughness of 0 12 - 0 15 inn among all three aminosilane films Stability tests indicate that APDIPES films retain most of their integrity at pH 10 for several hours and are more stable than APTEs or APDMES layers The films also showed good stability against storage in the laboratory ToF-SIMS of these samples showed expected peaks, such as CN-, as well as CNO-, which may arise from an interaction between monolayer amine groups and silanols. Optical absorption measurements on adsorbed cyanine dye at the surface of the aminosilane films show the formation of dimer aggregates on the surface This is further supported by ellipsometry measurements. The concentration of dye on each surface appeals lobe consistent with the density of the amines

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.