摘要:

Discharge characteristics have been investigated of a laser device in which the surface‐discharge plasma from a dielectric surface is used as a preionizer and an electrode, the plasma electrode. It is demonstrated that a highly homogeneous discharge can be obtained by optimizing the delay time of the main volume discharge with respect to the surface discharge. The output energy from the device used as a N2laser is also discussed.

ISSN:0003-6951    

DOI:10.1063/1.97311

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A phased‐array semiconductor laser with identical coupled waveguides is designed to favor a uniform, stable supermode. All but the two outermost waveguides are equally spaced with the placement of the first andNth guides chosen so as to increase their coupling coefficient by &sqrt;2. The lowest and highest order supermodes have a uniform near‐field intensity envelope and utilize the injected charges more efficiently. Whichever of these is favored at threshold should remain stable with increasing pumping or under modulation.

ISSN:0003-6951    

DOI:10.1063/1.97312

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

In a degenerate four wave mixing system, the phase conjugate signal from a transmission grating recorded in a Bi12SiO20crystal is measured at various temperatures and the results are compared with theory. The diffraction efficiency &eegr; has a maximum value at a temperature above room temperature. The dynamic range in &eegr; vsItimproves with increasing temperature, whereItis the total intensity of the laser beam incident on the crystal. The experimental results are interpreted in terms of the temperature dependence of the effective modulation depth of the transmission grating and the diffusion field in the crystal.

ISSN:0003-6951    

DOI:10.1063/1.97313

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Instabilities in self‐pulsing semiconductor diode lasers in a long external ring cavity are reported. The frequency of the self‐pulsations increases in discrete steps with the injection current and the light‐current characteristic displays kinks at these steps. The observed frequencies are multiples of the external cavity resonance and the laser output is unstable when biased at currents corresponding to these kinks. Similar observations have been made in various cavities and other laser diodes.

ISSN:0003-6951    

DOI:10.1063/1.97314

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Nonlinear refractive index changes in 299 A˚ multiple quantum well GaAs were obtained directly by measuring Fabry–Perot transmission peak shifts. These changes crosscheck those obtained by Kramers–Kronig transformations of the nonlinear absorption under identical pumping conditions. High intensities saturate the exciton, so that nonlinear refractive index changes are dominated by nonresonant contributions. Thermal refractive index changes were also measured directly.

ISSN:0003-6951    

DOI:10.1063/1.97315

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The interface reaction induced by means of rapid thermal melting (RTM) of the Ni(30 nm)/Al(10 nm)/Si system, using heat treatment times of a few seconds at temperatures around the aluminum melting point, has been investigated. The RTM occurred at the Al‐Si eutectic melting temperature (577 °C). As a result of this melting a polycrystalline intermediate layer, 60 nm thick, composed of NiSi and Ni2Si was formed adjacent to the Si substrate with a relative smooth interface while the Al was repelled to the outer region of the contact and two successive separate layers of polycrystalline Al3Ni and Ni(Al0.5Si0.5) were formed, both 10 nm thick. The results indicate that RTM can be used to obtain a unique interface reaction in a controlled manner.

ISSN:0003-6951    

DOI:10.1063/1.97316

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The reduction of the work function of a polycrystalline W surface due to Cs+bombardment has been investigated in the incident energy range below 500 eV. Upon exposure of the surface to a Cs+beam, the work function decreases until a steady state is reached with a total Cs+dose of less than 1×1016ions/cm2. A minimum steady state work function surface is produced at an incident energy of ≊40 eV and the steady state work function rapidly increases with bombarding energy. Coverages are significantly lower than that produced on Mo for the same bombarding energies. Auger electron spectroscopy is used to confirm surface coverages. The cesium surface concentration is determined by reflection, sputtering, and implantation.

ISSN:0003-6951    

DOI:10.1063/1.97317

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The interface morphology of gold contacts on ultrahigh vacuum (UHV) cleaved, air‐exposed, and chemically prepared GaAs surfaces has been studied by electron microscopy. Diodes formed on atomically clean cleaved (110) GaAs surfaces, subsequently annealed at 405 °C, were found to have flat interfaces. In contrast, diodes formed on air‐exposed and chemically prepared GaAs surfaces, also subsequently annealed at 405 °C, were found to have rough and uneven interfaces with a large number of protrusions extending into the semiconductor. They have different orientation relationships with the GaAs substrate than the diodes preparedinsituin UHV. The results of this study show that, upon annealing, the interfacial chemistry and morphology depend strongly on the surface preparation of GaAs before gold deposition.

ISSN:0003-6951    

DOI:10.1063/1.97318

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Recombination‐induced defect reactions are reversible in principle; i.e., any recombination (or trapping) process that induces defect formation can also induce recovery of that defect. This reversibility principle applies to crystalline and amorphous semiconductors. Although the rates in the two directions are generally quite different, evidence is cited indicating that in hydrogenated amorphous silicon they may be comparable, and offer new explanations for several observations. Illustrative rate equations are presented along with a series of testable experimental predictions.

ISSN:0003-6951    

DOI:10.1063/1.97319

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A model is described, based on chemical bonding and lattice matching considerations, to account for the heteroepitaxy of CdTe on (100) GaAs substrate. The two main features of the proposed model are that the initial growth of CdTe starts with the formation of stable clusters of chemically bond Te, and that two types of cluster configurations are obtained depending only on the atomic structure of the (100)GaAs surface: the first one, made up of tetrahedral unit cells is formed on an As‐deficient surface and leads to (111) orientation, whereas the second one, formed by twin‐tetrahedral structures developed on an As‐ or Ga‐stabilized surface gives rise to (100) orientation.

ISSN:0003-6951    

DOI:10.1063/1.97320

出版商:AIP    

年代:1986

数据来源: AIP