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

Few papers have been published about the unique materials aspects of damage accumulation during very high-energy (3 MeV boron and 5 MeV phosphorus) ion implantation. The damage created in the regions near the projected range and near surface regions will create a significant amount of defects. The creation of these defects are caused by two different mechanisms. The near surface defects are dominated by vacancies while the range projection defects are dominated by interstitials. Understanding the impact of these defects will require knowledge of the interactions with their annealing characteristics and size, density and complexing with impurities. Implantation was done into epitaxial grown layers on Czochralski substrates which were processed through subsequent annealing cycles which simulates a typical advanced CMOS process to understand the formation of the defects in the near surface and projected range. The material characterization was done by using TEM (plan view and cross section), selective silicon etching and other appropriate techniques for quantification of the damage.

Defect formation in MeV ion implantation of boron and phosphorus

Electron cyclotron resonance-metalorganic molecular beam epitaxy (ECR-MOMBE) has been used to deposit cubic and hexagonal gallium nitride (GaN) on various substrates, namely GaAs, ZnO and Al2O3. This paper will report on the effect of the growth rate of the GaN layer on the surface morphology, as analyzed using scanning electron microscopy (SEM). Structural characterization of this material was conducted using cross-sectional transmission electron microscopy (XTEM) and x-ray diffraction. Conditions such as pre-deposition annealing, growth rate and growth temperature are critical in determining the phase and crystallinity of the deposited layers. These parameters were optimized to obtain the cubic GaN phase on GaAs substrates and single crystal wurtzitic GaN on ZnO and Al2O3 substrates.

Structural Characterization of GaN Grown By Electron Cyclotron Resonance-Metalorganic Molecular Beam Epitaxy (ECR-MOMBE)

Several different types of GaAs-AlGaAs heterostructures were grown on Si substrates by MOCVD. The defect density in as-grown samples (~10 8 cm −2 ) was similar to that of GaAs layers grown directly on Si, and the crystalline quality of the material was observed to improve slightly with post-growth annealing at 900°C. We examined the diffusion of both Si and Zn dopants during this type of annealing and found only a small amount of redistribution of both species. Laser annealing of GaAs-on-Si was also examined as a method of reducing the defect density in the material - we observed substantial improvements in surface quality, but no change in sub-surface crystalline quality.

Growth and Characterization of GaAs-Based Heterostructures on Si By Mocvd

High energy (56 MeV) oxygen implants into Si, GaAs and InP give rise to sharp, non-Gaussian depth profiles with the distributions skewed towards greater depths. This skewness is probably the result of channeling, and it is a common feature of MeV implants into semiconductors. The ratio of the peak concentration in the depth profile to the concentration at the surface is ≥10 3 for each material, and the full width at half maximum of each profile is ∼2 μm. The experimental projected ranges for the oxygen are ∼31 μm in GaAs, ∼36 μm in InP and ∼46 μm in Si. These are ∼10% larger than the values predicted by the PRAL code. The photoluminescence intensity from the top 1 μm from the surface of both GaAs and InP is reduced by more than an order of magnitude for 56 MeV oxygen implants at a dose of 1.3 × 10 15 cm −2 , due to point defect introduction in this region. Potential applications for these high energy implants in electronic and photonic device fabrication will be discussed.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1946427400519745

Characteristics of 56 Mev Oxygen Implantation into Si and III-V Semiconductors

Transmission electron microscopy has been combined with time-resolved reflectivity and ion channeling to study the effects of regrowth temperature and carbon introduction by ion implantation on the solid phase epitaxial regrowth (SPER) of strained 2000{Angstrom}, Si{sub 0.88}Ge{sub 0.12}/Si alloy films grown by molecular-beam epitaxy (MBE). Relative to the undoped layers, carbon incorporation in the MBE grown SiGe layers prior to regrowth at moderate temperatures (500--700C) has three main effects on SPER: these include a reduction in SPER rate, a delay in the onset of strain-relieving defect formation, and a sharpening of the amorphouse-crystalline (a/c) interface, i.e., promotion of a two-dimensional (planar) growth front. Recrystallization of amorphized SiGe layers at higher temperatures (1100C) substantially modifies the defect structure in samples both with and without carbon. At these elevated temperatures treading dislocations extend completely to the Si/SiGe interface. Stacking faults are eliminated in the high temperature regrowth, and the treading dislocation density is slightly higher with carbon implantation.

/pdf/the-effects-of-rapid-recrystallization-and-ion-implanted-2f3pnx1ghk.pdf

Kevin S. Jones

Papers

Defect formation in MeV ion implantation of boron and phosphorus

Structural Characterization of GaN Grown By Electron Cyclotron Resonance-Metalorganic Molecular Beam Epitaxy (ECR-MOMBE)

Growth and Characterization of GaAs-Based Heterostructures on Si By Mocvd

Characteristics of 56 Mev Oxygen Implantation into Si and III-V Semiconductors

The Effects of Rapid Recrystallization and Ion Implanted Carbon on The Solid Phase Epitaxial Regrowth of Si1−xGex Alloy Layers On Silicon