摘要:

A Monte Carlo code for simulation of electron, ion and fast neutral transport was developed to model the spatial distribution of excitation under nonequilibrium conditions at very high electric field to gas number density ratios (E/N) and low currents. The code includes the most detailed representation of electron scattering and transport including the reflection and multiplication at the anode and simulation of ion and fast neutral transport for realistic geometry of the experiments of B. M. Jelenkovic´ and A. V. Phelps [Phys. Rev. A36, 5310 (1987)] and V. T. Gylys, B. M. Jelenkovic´, and A. V. Phelps [J. Appl. Phys.65, 3369 (1989)]. A good agreement between the simulations and experimental data was achieved by using reasonable data for scattering cross sections from the literature. Simulations confirm the model proposed by A. V. Phelps, B. M. Jelenkovic´ and L. C. Pitchford [Phys. Rev. A36, 5327 (1987)] of transport and excitation kinetics at very highE/Nwhere fast neutral excitation is the dominant process for second positive(2+)band of nitrogen. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.364089

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Electromigration threshold, the product of current density,j, and the threshold length,lth,was measured for unencapsulated thin-film Cu conductors using edge-displacement techniques.jlthwas measured between 175 and 275 °C, and was found to be temperature dependent above 200 °C wherejlthdecreased with increasing temperature. It is suggested that the temperature dependence of the electromigration threshold may be obtained by considering the effects of the changing deformation mechanisms with changing temperature. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363894

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

High resolution x-ray photoelectron spectroscopy has been used to determine the valence band alignment at ultrathin SiO2/Si interfaces. In the oxide thickness range 1.6–4.4 nm the constant band-offset values of 4.49 and 4.43 eV have been obtained for the dry SiO2/Si(100) and the wet SiO2/Si(100) interfaces, respectively. The valence band alignment of dry SiO2/Si(111) (4.36 eV) is slightly smaller than the case of the dry SiO2/Si(100) interface. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363895

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have measured the Shubnikov–de Haas (SdH) effect in &dgr;-doped AlAs0.56Sb0.44/In0.53Ga0.47As heterostructures and observed a population of the second subband. Using the persistent photoconductivity effect we increased the electron density from 26.73 to 28.20×1011cm−2in the first subband and 6.61 to 7.20×1011cm−2in the second. The onset of the second subband population occurs when the first subband is filled to a density of 11.56×1011cm−2. From the nonparabolic band approximation we calculated the effective masses in both subbands before illumination. The effective mass for the second subband was evaluated using the temperature dependence of the SdH amplitude. Its value agrees well with the values obtained from thek⋅papproximation and infrared cyclotron resonance measurements. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363896

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The absorption spectrum in the 9–11 &mgr;m range of both undeformed and plastically deformed AgBr crystals and polycrystalline optical fibers was investigated by tunable laser calorimetry. The observed spectral features are discussed in terms of the crystal defect structure. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363897

出版商:AIP    

年代:1997

数据来源: AIP