摘要:

A model for the evolution of stacking faults in silicon during oxidation and during aging of silicon containing oxygen is proposed. Based on the proposed mechanism, the observed role of dislocations, point‐defect clusters constituting the swirl pattern, and abrasion‐induced strain in the generation of stacking faults can be accounted for in a unified manner.

ISSN:0003-6951    

DOI:10.1063/1.89292

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Singular instabilities at crystal growth interfaces of group‐IV and III‐V semiconductors lead to as‐grown surfaces optical devices, however, requirethe achievement of smoth planar layers. We consider the stability of surfaces with respect to singular instabilities and show that stable planar growth interfaces occur at slight deviati8ons from the singular orientation where monatomic growth steps are uniformly arrayed to minimize the interfacial energy resulting from step‐step attractive interactions. These results are applied to the elimination of crystal growth terraces in LPE AlGaAs‐GaAs laser material. Similar considerations appear to explain pyramid formations on CVD Si and on MBE InP.

ISSN:0003-6951    

DOI:10.1063/1.89293

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

We have carried out acoustic pulse echo measurement with 2‐nsec‐wide pulses. These are used to excite a zinc oxide layer deposited on a conically shaped sapphire buffer rod 2 mm in diameter at the tip of the cone. We have found that an easy way to make contact between the sapphire rod and a solid material under study is by means of a gold foil. We have measured the thickness of a nickel plating on aluminum of the order of 50 &mgr;m, and that of a 134‐&mgr;m‐thick glass slide to within 2%.

ISSN:0003-6951    

DOI:10.1063/1.89294

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Transient nuclear magnetic resonance (NMR) measurements on3He, generated by &bgr; decay and contained in aging titanium tritide (TiH1.8), have been carried out. The experiments were conducted over a period of about three years during which the rate of helium evolution from the sample abruptly increases. Qualitative analysis of the temperature dependence of the3He NMR correlates the onset of rapid increase in release rate with the precipitation of large bubbles within the solid. Further consideration suggests these bubbles are preliminary stages for release, since only a small fraction (<10%) of the3He in TiH1.8is ever observed in this configuration. This is the first data which directly infers3He bubbles at the time of release, although blisters have been observed in earlier experiments.

ISSN:0003-6951    

DOI:10.1063/1.89295

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

A model is developed for the effect of atmospheric dust on fiber strength. It is assumed that dust striking the fiber as it is formed sticks to form flaws. Comparison of the model with experimental data shows that it provides a reasonable description and can be useful in interpreting fiber strength.

ISSN:0003-6951    

DOI:10.1063/1.89296

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Picosecond optical pulses are used to switch a GaAs slab in a charged line pulser. The repetition rate of the device is 1 GHz. The effect of the Ridley‐Watkins‐Hilsum mechanism on the device performance is discussed.

ISSN:0003-6951    

DOI:10.1063/1.89297

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Long‐term operating‐life data are reported for (AlGa)As cw laser diodes. The use of half‐wave Al2O3facet coatings is shown to eliminate facet erosion, allowing stable diode operation at constant current for periods in excess of 10 000 h.

ISSN:0003-6951    

DOI:10.1063/1.89298

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

In reduced LiNbO3 : Mn both the photorefractive sensitivity and the simultaneously measured photocurrent result from drift with a polarization‐dependent effective ’’internal field’’ of about 6 kV/cm. In reduced undoped LiTaO3the observed difference in applied fields of the minimum photorefractive sensitivity and zero photocurrent imply charge transport is by a mechanism that cannot be completely described by diffusion and drift in an electric field. The direct measurement of the harmonic content of phase gratings written in several LiNbO3and LiTaO3crystals shows termination of charge‐transport results from the space‐charge field of the hologram.

ISSN:0003-6951    

DOI:10.1063/1.89299

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Second harmonic generation of mode‐locked pulses in ADP and KD*P from 532 to 266 nm with 85% conversion is reported. Two‐photon absorption coefficients are measured for the two materials and found to be relatively unimportant in the limitation of harmonic conversion compared to the effects of phase mismatch and dispersion.

ISSN:0003-6951    

DOI:10.1063/1.89300

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Linear intensity modulation of several percent in fiberguide transmission caused by flexural vibrations has been observed in bent fiberguides and attributed to modulated bending loss. Measurements of bending loss are presented which support this interpretation.

ISSN:0003-6951    

DOI:10.1063/1.89301

出版商:AIP    

年代:1977

数据来源: AIP