摘要:

Partially damaged self‐ion implanted Si(100) has been irradiated by a ruby laser pulse (&lgr;=0.69 &mgr;m,tp=15 ns). Channeling effect technique measurements and TEM micrographs show the reordering of the implanted layer in the laser energy range 1.5–2.5 J/cm2. No polycrystalline transition has been detected. Calculations in terms of local melting of the disordered zone explain the experimental data.

ISSN:0003-6951    

DOI:10.1063/1.91260

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The self‐diffusion preexponential factorD0=8.0 cm2/s and activation energyQ=4.1 eV for intrinsic silicon have been determined with the ( p,&ggr;) resonance broadening method in the temperature region 900–1100 °C, in a first application of this method to self‐diffusion measurements. Its suitability was tested by extending the self‐diffusion measurements to lower temperatures than those performed with other methods.

ISSN:0003-6951    

DOI:10.1063/1.91261

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A clean surface of a palladium silicide grown on a Si(111) plane has been studied by Auger electron spectroscopy. Heat treatment of the silicide in the temperature range 250–600 °C causes the accumulation of a thin layer of elementary Si over its surface. The accumulated thickness has been estimated to be about 3 A˚ and does not depend on heating temperatures and periods examined.

ISSN:0003-6951    

DOI:10.1063/1.91262

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

In some photoelectrical and photochemical devices, energy conversion may occur before thermal equilibrium within the electronic bands of the absorber. A statistical thermodynamic argument shows that such hot‐transfer devices cannot have an efficiency greater than that of an ideal device in which thermalization precedes energy conversion.

ISSN:0003-6951    

DOI:10.1063/1.91263

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The energy density of states in a Si grain boundary has been quantitatively determined for the first time. Since the deconvolution scheme used in this determination is a technique previously unapplied to real materials, the applicability of the model and the validity of the results were experimentally verified by comparing conductance and capacitance data. Additionally, a high‐voltage varistor characteristic (highly non‐Ohmic current) was observed. This shows for the first time that a simple grain boundary without intergranular additives is capable of a strong varistor behavior (nonlinearity coefficient &agr;≳20).

ISSN:0003-6951    

DOI:10.1063/1.91264

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The successful fabrication and demonstration of an InP optoelectronic switch is reported. The results obtained suggest that this device may be better suited for high‐speed analog signal processing applications than previously reported Si and GaAs switches. In experiments using cw mode‐locked lasers, the switches have exhibited an on‐state impedance of 45 &OHgr; for 40pJ of incident laser energy and an inherent rise time of 30 psec. In addition, the switches have been used to generate a train of 70‐psec‐wide pulses at a 900‐MHz repetition rate, and to sample a 68.9‐MHz sine wave at 275 MS/sec with an accuracy to 0.2 dB (98%) and an on‐off ratio of 40 dB.

ISSN:0003-6951    

DOI:10.1063/1.91265

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A 0.64‐cm‐diam. Cu‐Nb composite rod was continuously melted at 1800 °C, then resolidified in a controlled large temperature gradient (∼ 400 °C/cm) to produce a microstructure of aligned [directionally solidified, (DS)] dendrites in a copper matrix. Primary dendrite arm sizes of ∼50, 20, and 10 &mgr;m were measured for growth rates of 5.6×10−4, 1.7×10−2, and 0.11 cm/sec, respectively. Higher growth rates produced an equiaxed structure typical of chill casting. After processing, the overallJcof the DS wires and the effect of stress onJcwere comparable to those of chill‐cast specimens. The atomic fraction of Nb converted to Nb3Sn increased with decreasing filament size, andTcwas approximately 17.6 K for the DS alloys.

ISSN:0003-6951    

DOI:10.1063/1.91239

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A method is described for automating a technique which is used to sample transition duration (rise time) in superconducting logic circuits. The method is based on measuring the time at which a biased Josephson junction switches under the influence of an applied signal. The system transition duration is limited primarily by time jitter which is estimated to be 7 ps. Transition durations of as little as 9 ps have been observed.

ISSN:0003-6951    

DOI:10.1063/1.91266

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Multiple‐quantum interference in a superconducting interferometer is used for analog‐to‐digital conversion. The simple fully parallel four‐bit converter which is described is the first known use of this effect in a digital circuit. Sampling rates of 2×108per second were achieved, and much higher rates appear possible.

ISSN:0003-6951    

DOI:10.1063/1.91238

出版商:AIP    

年代:1979

数据来源: AIP