摘要:

We report the design and basic operating characteristics of a co‐axial radio‐frequency discharge carbon dioxide laser which employs a multipass Herriott cell folding system within a linear resonator. A continuous wave laser power output of 65 W was obtained from a device 35 cm in length in a high‐quality TEM00mode without gas flow. The characteristics of transverse rf discharges and the image rotation properties of such resonators indicate that this approach may be scalable to provide much higher laser powers with excellent transverse mode properties.

ISSN:0003-6951    

DOI:10.1063/1.98396

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Electrically pumped, surface‐emitting distributed feedback lasers were for the first time demonstrated without any facet reflections. The devices contained second‐order gratings etched into a thinp‐AlGaAs cladding layer surface. A gold ohmic contact deposited directly onto thep‐AlGaAs grating surface provided strong coupling to the waveguide mode. Single spatial mode devices with low divergence output beams and single frequency spectra were obtained at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.98397

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Optical nonlinear switching and bistability due to increasing absorption have been observed in single‐crystal ZnSe waveguides with contrast ratios of 16/1 and switching times of 10 &mgr;s at 15 mW of argon laser light. Switching energy is improved over the bulk by a factor of 200.

ISSN:0003-6951    

DOI:10.1063/1.98398

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Optical transmission spectra of PbTe/Pb1−xEuxTe (x=0.05) superlattices were measured at 300 K. The superlattices were prepared on thick Pb1−xEuxTe buffers grown on KCl (100) substrates using the hot wall epitaxy technique. Clear steplike absorptions corresponding to the interband electron transitions between subbands (n=1,2,3 ton=1,2,3) were observed for the first time for the PbTe/Pb1−xEuxTe superlattice. The experimental absorption edges agreed very well with theoretical ones calculated assuming the conduction‐band offset is equal to that of the valence band.

ISSN:0003-6951    

DOI:10.1063/1.98372

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

High‐resolution x‐ray and ultraviolet photoemission spectroscopies have been applied to study the initial formation of the Cr‐ and Cu‐polyimide interfaces. A model for the growth modes of these two interfaces is proposed based on comparison of experimental results with trends derived from quantum‐chemical calculations.

ISSN:0003-6951    

DOI:10.1063/1.98373

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Images of graphite surfaces that are covered with oil reveal the hexagonal rings of carbon atoms. Images of a sodium chloride surface, protected from moisture by oil, exhibit a monoatomic step. Together, these images demonstrate the potential of atomic force microscopy (AFM) for studying both conducting and nonconducting surfaces, even surfaces covered with liquids. Our AFM uses a cross of double wires with an attached diamond stylus as a force sensor. The force constant is ≊40 N/m. The resonant frequency is ≊3 kHz. The lateral and vertical resolutions are 0.15 nm and 5 pm.

ISSN:0003-6951    

DOI:10.1063/1.98374

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The effect of the implantation of silicon ions on the anomalous transient diffusion of ion‐implanted boron is investigated. It is found that silicon ion fluences well below that necessary to amorphize the lattice substantially reduce the anomalous transient diffusion of subsequently implanted boron. The sheet resistance, however, is increased by the additional silicon implant. The implantation of silicon ions into activated boron layers causes additional anomalous diffusion at substantial distances beyond the range of the silicon ions. The anomalous motion is also reduced in regions where the damage is greater. The effects can be explained in terms of the generation of point defect clusters which dissolve during anneal and the sinking of point defects in the regions of high damage by the formation of interstitial type extended defects.

ISSN:0003-6951    

DOI:10.1063/1.98375

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

In this study we examine the permeating of hydrogen intop‐type silicon during low‐energy hydrogen ion beam bombardment by monitoring boron doping deactivation. This examination is done for various times and two different exposure temperatures. In addition we explore the effect of temperature during subsequent isochronal anneals on the recovery of silicon exposed to a hydrogen ion beam. As a result of these studies, it is found that there are two distinct permeation regions. Each may be characterized by its own apparent diffusion coefficient, activation energy, and recovery process.

ISSN:0003-6951    

DOI:10.1063/1.98376

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We report the observation of electric field induced exciton energy shifts and photoluminescence quenching in GaInAs/InP multiple quantum wells. We have measured both the photocurrent and photoluminescence spectra from 100 A˚ wells contained withp+‐ andn+‐InP layers in a conventionalp‐i‐nstructure; reverse bias voltages of up to 12 V were applied. The exciton peaks in the photocurrent spectrum are seen to broaden and shift to lower energy; the photoluminescence peak, which is due ton=1 excitonic and free‐carrier recombination, also shifts to lower energy and is completely quenched at high voltages. These results are similar to those reported previously for GaAs quantum wells and ascribed to the quantum‐confined Stark effect.

ISSN:0003-6951    

DOI:10.1063/1.98377

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Plasma hydrogenation for 3 h at 250 °C of GaAs layers grown directly on Si substrates by metalorganic chemical vapor deposition, followed by a 5‐min, 400 °C anneal to restore the passivated shallow donor electrical activity, increases the reverse breakdown voltage of Schottky diode structures from 2.5 to 6.5 V. This improvement appears to be a result of the passivation by atomic hydrogen of defects such as threading dislocations caused by the large (4%) lattice mismatch between GaAs and Si. A reduced Schottky barrier height is exhibited by hydrogenated samples, consistent with As depletion of the surface occurring during the long duration plasma processing.

ISSN:0003-6951    

DOI:10.1063/1.98378

出版商:AIP    

年代:1987

数据来源: AIP