摘要:

An unconditionally stable numerical procedure is developed to integrate the stiff differential equation associated with the flow rule for viscoplasticity used by Swegle and Grady [J. Appl. Phys.58, 692 (1985)] to predict shock structure. Following the work of Rubin [J. Appl. Math. Phys. ZAMP40, 846 (1989)] the flow rule is integrated implicitly and is converted into a scalar equation. It is shown that for the Swegle–Grady model this scalar equation reduces to a quadratic equation that can be solved without iteration.

ISSN:0021-8979    

DOI:10.1063/1.346682

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Evidence is presented for strong correlation between new donors and rodlike defects generated at 650 °C in phosphorus‐doped, carbon‐lean Czochralski silicon preannealed at 450 °C. It is proposed that there are, in general, several types of new donors depending on experimental conditions, and one type of new donor, which is generated preferentially under the above special condition, arises from rodlike defects.

ISSN:0021-8979    

DOI:10.1063/1.346683

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The authors have studied the characteristics of tungsten (W) and carbon (C) thin films, and W/C multilayers prepared by ArF excimer‐laser‐induced chemical vapor deposition using tungsten hexafluoride and benzene gases. Amorphous W and C films with very smooth surfaces were obtained at substrate temperatures of 100–200 °C and 100–300 °C, respectively. In small‐angle x‐ray scattering measurements for the multilayers deposited at 200 °C, a first order of multilayer reflections were clearly observed. Furthermore, Auger electron spectroscopy showed that W and C layers in the multilayers were periodically deposited.

ISSN:0021-8979    

DOI:10.1063/1.346684

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Low temperature ion beam mixing rates for Cu‐Ti, Ni‐Ti, and Fe‐Ti layers have been found to be significantly lower than predicted by a popular semi‐empirical thermal spike model. It has been proposed that the unavoidable hydrogen contamination of the as‐deposited Ti films may have reduced the mixing rates, but the measurement of even lower mixing rates for Fe‐V and Fe‐Co bilayers shows the discrepancy to be more fundamental. Still, a systematic dependence on heat of mixing suggests that some sort of diffusional (thermal spike?) mechanism is involved.

ISSN:0021-8979    

DOI:10.1063/1.346685

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

It is demonstrated that uniform silver‐gallium alloy films, containing up to 30% gallium, can be controllably and reproducibly fabricated by electron‐beam evaporation from a single alloy source. As expected from bulk thermodynamic arguments, these films are metallurgically stable with respect to GaAs up to their melting point. The alloying of silver with gallium results in a substantial reduction inn‐type barrier height. Analogous increases in barrier height were observed for contacts top‐type material. Barrier heights as low as 0.59–0.62 eV were measured for annealed &zgr;‐AgGa contacts ton‐type material.

ISSN:0021-8979    

DOI:10.1063/1.346686

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The feasibility of adapting scanning tunneling microscope (STM) technology to investigate the transition from reversible to irreversible behavior in mechanical systems is demonstrated. Using an STM with a graphite sample, both regimes of reversible and irreversible response to electrostrictive cycling are observed.

ISSN:0021-8979    

DOI:10.1063/1.346687

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A two‐band transfer matrix method has been developed to study tunneling currents in narrow gap and interband tunnel structures. This relatively simple model gives good agreement with recently reported experimental results for InAs/AlSb/InAs/AlSb/InAs double‐barrier heterostructures and InAs/AlSb/GaSb/AlSb/InAs resonant interband tunneling devices, and should be useful in the design of new interband tunneling devices.

ISSN:0021-8979    

DOI:10.1063/1.346688

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

For the first time the growth of polycrystalline CdS films by the gradient recrystallization and growth technique on silicon, quartz, and glass substrates is reported. X‐ray diffraction, photoluminescence, scanning electron microscopy, and microprobe studies were used for their characterization. This preliminary study shows that this technique is suitable for growing CdS films with larger grain sizes than those obtained by conventional evaporation methods. The photoluminescence studies show that the emission spectrum of the films deposited on silicon is comparable to single‐crystal CdS.

ISSN:0021-8979    

DOI:10.1063/1.346689

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Gas evolution experiments have been performed on hydrogenated amorphous carbon (a‐C:H) films prepared by plasma deposition. Two series of films are studied: in series I, C2H2is used as a process gas at a fixed bias voltage while the gas pressure is varied, and in series II, CH4is employed at a fixed gas pressure, and the bias voltage is changed. The results are compared to infrared absorption data and density measurements and support the presence of a void network in the amorphous material, the extent of the void network depending on the deposition conditions.

ISSN:0021-8979    

DOI:10.1063/1.346690

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The surface photovoltage (SPV) technique is often used to determine the diffusion length in hydrogenated amorphous silicon (a‐Si:H). The use of this technique fora‐Si:H is disputed because it has been shown by computer simulations that the drift component is not negligible compared to the diffusion current in SPV measurements ona‐Si:H. For crystalline semiconductors the SPV technique gives the minority‐carrier diffusion length while the drift current is negligible. We found from the solution of the transport equations that the SPV technique can be used in the case ofa‐Si:H, but gives the ambipolar diffusion length which consists of the mobility and lifetime of both holes and electrons. However, the termdiffusionlength is misleading since the hole drift current and the hole diffusion current are of the same order of magnitude fora‐Si:H. This result is in accordance with the results of the computer simulations mentioned earlier. The drift current assists the diffusion current and increases the measured diffusion length by a factor (2)1/2compared to the situation with diffusion current alone.

ISSN:0021-8979    

DOI:10.1063/1.346691

出版商:AIP    

年代:1990

数据来源: AIP