J. Appl. Cryst.の発刊に際して

This paper gives the 2010 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. The 2010 adjustment takes into account the data considered in the 2006 adjustment as well as the data that became available from 1 January 2007, after the closing date of that adjustment, until 31 December 2010, the closing date of the new adjustment. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2010 set replaces the previously recommended 2006 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.

/pdf/codata-recommended-values-of-the-fundamental-physical-4bsdant71c.pdf

CODATA Recommended Values of the Fundamental Physical Constants: 2006

Fuel cells are uniquely capable of overcoming combustion efficiency limitations (e.g., the Carnot cycle). However, the linking of fuel cells (an energy conversion device) and hydrogen (an energy carrier) has emphasized investment in proton-exchange membrane fuel cells as part of a larger hydrogen economy and thus relegated fuel cells to a future technology. In contrast, solid oxide fuel cells are capable of operating on conventional fuels (as well as hydrogen) today. The main issue for solid oxide fuel cells is high operating temperature (about 800°C) and the resulting materials and cost limitations and operating complexities (e.g., thermal cycling). Recent solid oxide fuel cells results have demonstrated extremely high power densities of about 2 watts per square centimeter at 650°C along with flexible fueling, thus enabling higher efficiency within the current fuel infrastructure. Newly developed, high-conductivity electrolytes and nanostructured electrode designs provide a path for further performance improvement at much lower temperatures, down to ~350°C, thus providing opportunity to transform the way we convert and store energy.

http://science.sciencemag.org/content/sci/334/6058/935.full.pdf

Lowering the Temperature of Solid Oxide Fuel Cells

Review on recent progress of nanostructured anode materials for Li-ion batteries

The role of extended and point defects, and key impurities such as C, O, and H, on the electrical and optical properties of GaN is reviewed. Recent progress in the development of high reliability contacts, thermal processing, dry and wet etching techniques, implantation doping and isolation, and gate insulator technology is detailed. Finally, the performance of GaN-based electronic and photonic devices such as field effect transistors, UV detectors, laser diodes, and light-emitting diodes is covered, along with the influence of process-induced or grown-in defects and impurities on the device physics.

Gan : processing, defects, and devices

The oxidation of silicon is known to inject interstitials, and the presence of silicon–germanium (SiGe) alloys at the Si/SiO2 interface during oxidation is known to suppress the injection of silicon self-interstitials This study uses a layer of implantation-induced dislocation loops to measure interstitial injection as a function of SiGe layer thickness The loops were introduced by a 50 keV 2 × 1014 cm−2 P+ room-temperature implantation and thermal annealing Germanium was subsequently introduced via a second implant at 3 keV Ge+ over a range of doses between 17 × 1014 cm−2 and 14 × 1015 cm−2 Results show that upon oxidizing at 850 °C for 3 h or 900 °C for 70 min to condense the germanium at the Si/SiO2 interface, where if forms a Si05Ge05 alloy Upon subsequent oxidations of 850 °C for 6 h or 900 °C for 2 h, partial suppression of interstitial injection can be observed for sub-monolayer doses of germanium, and more than three monolayers of Si05Ge05 (14 × 1015 cm−2) are necessary to suppress interstitial injection below the detection limit during oxidation These results show that low-energy implantation of germanium can be used to eliminate or modulate injection of oxidation-induced interstitials

Quantification of germanium-induced suppression of interstitial injection during oxidation of silicon

Boron, a P-type dopant, experiences Transient Enhanced Diffusion (TED) via interstitials. The Boron TED and {311} dissolution rates are explored as a function of implant energy dependence. Silicon implants of 1014/cm2 at 20, 40, 80, and 160 keV were used to damage the surface of a wafer with an epitaxially grown boron marker layer. Samples were annealed at 750°C for 15 to 135 minutes and 800°C for 10 to 30 minutes to observe the diffusion exhibited by the marker layer and to correlate this with the dissolution of {311} type defects. The diffusion enhancement depends strongly on implant energy but the {311} dissolution rate is weakly dependent.

Energy Dependence of Transient Enhanced Diffusion and {311} Defect Kinetics

Transmission electron diffraction patterns of cross-sectional TEM samples of OMVPE ZnSe on GaAs indicate the existence of the hexagonal wurtzite phase in the epitaxial layers. The orientation relationship is (0002)//(111); (1120)//(220). Etching studies indicate the phase is internal not ion milling induced. The average wurtzite particle size is 80A-120A. Because of interplanar spacing matches it is easily overlooked. Electrical property measurements show a high resistivity (1010ω/square) which drops by four orders of magnitude upon rapid thermal annealing between 700°C and 900 °C for 3 sec. Implantation of Li and N have little effect on the electrical transport properties. The Li is shown to have a high diffusivity, a solid solubility of ≈1016/cm3 at 800°C and getters to the ZnSeA/aAs interface.

Observation of the Wurtzite Phase in OMVPE Grown ZnSe/GaAs: Effect on Implantation and Rapid Thermal Annealing

Effect of Surface Proximity upon Point Defects in Silicon

The effect of dose and energy on postannealing defect formation for high energy (mega-electron-volt) phosphorus implanted silicon has been studied using etch pit studies and transmission electron microscopy (TEM). Previous work has shown that after annealing there is a strong dependence of dislocation density threading to the surface on the implanted phosphorus dose and energy. A superlinear increase in threading dislocation density (TDD) with implant energy between 180 and 1500 keV is observed for a dose of 1×1014 cm−2. In addition as a function of ion fluence, there is a maximum in the threading dislocation density at a dose of 1×1014 cm−2 followed by a rapid decrease in TDD. Both the superlinear increase in TDD with increasing energy and the rapid decrease with increasing dose have been further investigated by TEM. A TEM study of these higher doses revealed formation of a strong bimodal loop distribution with small loops averaging <1000 A and large loops averaging around 1 μm in size. Over the dose ran...

Kevin S. Jones

Papers

Quantification of germanium-induced suppression of interstitial injection during oxidation of silicon

Energy Dependence of Transient Enhanced Diffusion and {311} Defect Kinetics

Observation of the Wurtzite Phase in OMVPE Grown ZnSe/GaAs: Effect on Implantation and Rapid Thermal Annealing

Effect of Surface Proximity upon Point Defects in Silicon

Threading dislocation evolution in mega-electron-volt phosphorus implanted silicon