摘要:

Phosphorus and boron ion implantations were performed at various energies in the 50 keV–4 MeV range. Range statistics ofP+andB+were established by analyzing the as-implanted secondary ion mass spectrometry depth profiles. Anneals were conducted in the temperature range of 1400–1700 °C using either a conventional resistive heating ceramic processing furnace or a microwave annealing station. The P implant was found to be stable at any annealing temperature investigated, but the B redistributed during the annealing process. The implant damage is effectively annealed as indicated by Rutherford backscattering measurements. For the250 keV/1.2×1015 cm−2P implant, annealed at 1600 °C for 15 min, the measured donor activation at room temperature is 34&percent; with a sheet resistance of4.8×102 &OHgr;/□.Thep-type conduction could not be measured for the B implants. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365236

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Plasma immersion ion implantation was used to implant oxygen ions into silicon with applied voltage pulses of −40 kV and 2.5&mgr;s length. Positive ions, O2+and O+, with a continuous energy distribution between 0 and 40 keV were implanted. Between3×104and3×105pulses, corresponding to nominal doses from2×1016to2×1017/cm2,were used. The resulting oxygen depth profiles were measured with elastic recoil detection analysis using 13.4 MeV&agr;particles. Rutherford backscattering was used to determine possible co-implanted contaminants. The obtained depth profiles were simulated using a linear superposition of calculated single-energy profiles. The results obtained for the energy distribution of the incident ions are compared with calculations obtained from a theoretical model, and the agreement is very good. The incident flux is found to be composed of 34(5)&percent; O2+and 66(5)&percent; O+ions with an Fe contamination of ∼0.5&percent;.©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365203

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Gallium sulfide single crystals have been irradiated with different thermal neutron doses. Defects introduced by neutron irradiation turn out to be optically active, giving rise to absorption bands with energies ranging from 1.2 to 3.2 eV. Bands lying in the band-gap exhibit Gaussian shape. Their energies and widths are independent of the irradiation dose, but their intensities are proportional to it. Thermal annealing is completed in two stages, ending at around 500 and 720 K, respectively. Centers responsible for the absorption bands are proposed to be gallium-vacancy-galliuminterstitial complexes in which the distance between the vacancy (acceptor) and the interstitial (donor) determines the energy and intensity of the absorption band, as well as the annealing temperature. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365204

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

SamariumLIIIx-ray absorption fine structure spectra for bothSm2+andSm3+-doped(100-X)B2O3XNa2O(X=10,15,20)glasses and bothSm2+andSm3+-doped85B2O3(15-X)Al2O3XNa2O(X=5,10)glasses were measured using synchrotron radiation. The oxygen coordination number of samarium inSm2+-doped glass is different from that of theSm3+-doped glass with the same composition while the nearest neighbor Sm–O distances are closely the same. The change of coordination numbers with alkali or aluminum addition was related to the variation of the optical hole width ofSm2+-doped glasses. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365205

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report on the use of time-resolved Raman scattering data to determine temperatures in liquid carbon tetrachloride shocked by step-wise loading to a peak pressure of 12 GPa. Changes in our previously reported experimental configuration have resulted in a significant improvement in the signal-to-noise ratio in the data and permitted us to analyze the stokes and antistokes intensities for more than one vibrational mode (314 and460 cm−1modes). Hence, better precision can be obtained for shock temperatures on the nanosecond time scales. Temperatures are reported in the 500–1000 K range with an experimental precision of approximately 8&percent;–10&percent;. Our data show that the equation of state for carbon tetrachloride reported in the literature provides temperature values that are significantly lower than the measured values. Various aspects of using Raman scattering data for determination of shock temperatures are discussed. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365206

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The compressive failure of soda-lime glass under uniaxial shock loading has been the subject of much recent discussion. Evidence of failure occurring behind a traveling boundary that follows a shock front has been accumulated and verified in several laboratories. Such a boundary has been called a failure wave. The variations in material properties across this front include complete loss of tensile strength, reduction in shear strength, lowered acoustic impedance and sound speed, and opacity to light. It in many ways resembles a phase boundary. While these observations are generally held to be true, there is no universally agreed mechanism for the process or processes that gives rise to the failure. It is the object of this work to present the results of plate impact experiments that aim to identify the mechanism by which the failure wave propagates. The experiments indicate that the failure is nucleated by the shock wave at surfaces, and that deliberately introducing flaws by roughening the surface speeds the fracture of the material leading to a failure wave close to the shock front. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365207

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Measurements of the thermal conductivity and specific heat of commercial 99.95&percent; purity annealed polycrystalline molybdenum in the temperature range of 0.1–1 K are reported. These thermal data and other published data on molybdenum and aluminum–magnesium alloys are used to calculate and compare cool-down and steady state thermal response of 1 kHz ultracryogenic resonant-mass gravitational wave detectors made of these materials. At temperatures below 100 mK, the Mo is shown to be far superior to the 5056 Al–Mg alloy with regard to temperature homogeneity in the resonant mass at the expected levels of residual heat leak. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365436

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Organic solvents like acetone can penetrate into poly(ethylene terephthalate) (PET). The model of case I (Fickian) and case II (swelling) is employed to study the phenomenon of mass transport. This model is successful in explaining the behavior of mass transport in an amorphous polymer, for example, poly(methyl methacrylate) (PMMA). The characteristic parameters, diffusivityDand velocityv,can be obtained from the analysis of experimental data. The mass transport in PET is different from that in PMMA. It is accompanied by a large-scale structural rearrangement, which leads to induced crystallization of the original amorphous state. This is the so-called “solvent-induced crystallization.” Acetone-induced crystallization was confirmed by x-ray diffraction. The differential scanning calorimetry thermograms of acetone-treated PET show that the crystallization peak disappears and the glass transition temperature decreases. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365208

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We show that the transient ion drift (TID) method, which is based on recording junction capacitance under constant reverse bias [A. Zamouche, T. Heiser, and A. Mesli, Appl. Phys. Lett.66, 631 (1995)], can be used not only for measurements of the diffusion coefficient of mobile impurities, but also to estimate the concentration of mobile species as part of the total dopant density. This is illustrated for CdTe, contaminated by Cu, and intentionally doped by Li or Ag and forCuInSe2.We show also that, with some restrictions, the TID method can be used if the mobile ions are major dopants. This is demonstrated using Schottky barriers on CdTe, andp–njunction devices in (Hg,Cd)Te, andCuInSe2.The values that we obtain for the diffusion coefficients (for Li, Ag, and Cu in CdTe and for Cu inCuInSe2) agree well with measured or extrapolated values, obtained by other methods, as reported in the literature. Furthermore, we could distinguish between diffusion and chemical reactions of dopants, as demonstrated for the case of Cu in CdTe and Ag-doped (Hg,Cd)Te. In the former case this allows us to separate copper-free from contaminated CdTe samples. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365563

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A methodology is introduced for predicting the effective thermal conductivity of arbitrary particulate composites with interfacial thermal resistance in terms of an effective medium approach combined with the essential concept of Kapitza thermal contact resistance. Results of the present model are compared to existing models and available experimental results. The proposed approach rediscovers the existing theoretical results for simple limiting cases. The comparisons between the predicted and experimental results of particulate diamond reinforced ZnS matrix and cordierite matrix composites and the particulate SiC reinforced Al matrix composite show good agreement. Numerical calculations of these different sets of composites show very interesting predictions concerning the effects of the particle shape and size and the interfacial thermal resistance. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365209

出版商:AIP    

年代:1997

数据来源: AIP