摘要:

A simple new method is described for probing acoustoelectric domains inn‐GaAs through their strong photoconductive response to a focused light beam. This permits a scan of the spatial distribution and propagation of the amplified acoustic flux in the sample. As a further application of the photoconductive response, a narrow propagating domain can be used to reveal an optical image projected onto the sample. The techniques are illustrated here primarily for extrinsic photoexcitation with Nd:YAG laser light.

ISSN:0003-6951    

DOI:10.1063/1.88363

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Measurements of the free‐free absorption coefficient in high‐pressure (50–400 psia) e‐beam‐excited rare‐gas plasmas have been used to deduce the temporal evolution of electron density in these systems. The measurements were carried out using a focused CO2laser beam passing through the excited region of the plasma. Comparison of theory and experiment in the early afterglow, where Penning ionization of excimers dominates the electron production, yields a room‐temperature rate coefficient of 8×10−11cm3/sec for this process in xenon.

ISSN:0003-6951    

DOI:10.1063/1.88364

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

An analytic model for space‐charge‐limited flow in relativistic diodes is presented which includes the effect of a transverse magnetic field below the critical field for magnetic insulation. Conditions for the validity of the model are investigated and comparison is made with recent experiments by Goldenetal.

ISSN:0003-6951    

DOI:10.1063/1.88365

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The interface state induced by 25‐keV electron beam irradiation in MOS capacitors havingp‐ andn‐type substrates with several different doping concentrations have been studied. For radiation dosage on or above the order of 1×10−5C/cm2, all of the radiation‐induced interface‐state distributions tend to have a similar shape which is asymmetrical about the midgap, independent of the type and concentration of the silicon dopants, and independent of the initial interface‐state distributions. The states in the upper half of the silicon band gap are acceptor type which peak around 0.2 eV from the midgap, whereas the states in the lower half of the band gap are donor type with a lower density. For radiation dosage below 1×10−7C/cm2the postradiation interface states are proportional to their initial values. An explanation based on the broken bond model is presented to account for the observations.

ISSN:0003-6951    

DOI:10.1063/1.88366

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Annealed ’’pure’’ gold films exhibit electromigration against the electron flow. In contrast, gold films deposited on a transition metal underlayer show mass flow in the same direction as the electron flow. Diffusion of the transition metal from the underlayer into the gold film, deduced from Auger analyses presented herein, is believed to be responsible for this reversal. A new experiment, utilizing an ’’inverted temperature profile’’ gives unambiguous results on the direction of electrotransport.

ISSN:0003-6951    

DOI:10.1063/1.88367

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

CeP5O14exhibits one emission band in the wavelength range 200–750 &mgr;m under cathode ray excitation. This band peaks at 335 nm and decays initially with &tgr;1=12 nsec. A somewhat slower decay with &tgr;2=36 nsec follows. These properties make the material suitable for fast scintillator applications, especially as a beam‐indexing phosphor in color cathode ray tubes.

ISSN:0003-6951    

DOI:10.1063/1.88368

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

After GaAs was implanted with 1015/cm260‐keV Zn ions at ambient temperature, annealing with a rf‐sputtered SiO2passivating layer resulted in the formation of the second‐phase structures ZnGa2O4at 800 °C and primarily Zn3As2at 600 °C. Possible relationships between the second‐phase structures and the electrical properties of the ion‐implanted annealed regions are discussed.

ISSN:0003-6951    

DOI:10.1063/1.88369

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Waveguiding of 1.0642‐&mgr;m radiation and nonphase‐matched second harmonic generation have been observed in a 200‐A˚‐thick GaP waveguide grown by molecular beam epitaxy on a (111) ‐oriented CaF2substrate.

ISSN:0003-6951    

DOI:10.1063/1.88370

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The wide‐band‐gap group II–group VI compound semiconductors have long been valued for their luminous efficiency, and an obvious application would bep‐njunction LED’s. However, these materials could only be madentype, notptype. Using an uncustomary technique, we have succeeded in making stable low‐resistivityp‐type ZnSxSe1−xand ZnSe by diffusion inton‐type substrates, and thereby have made low‐resistance LED’s. The diffusion process is carried out in two steps: a deposition step followed by a drive‐in. Gallium, indium, and thallium are used to make the materialptype. (i) The group IIIA element is present in doping quantities only. (ii)p‐type mobility values are presented as a function of hole concentration; temperature dependence establishes that the level is shallow. (iii) The LED’s have low resistance and the light output is linear with current above the barrier voltage. (iv) Generation current from the junction,n=2, is observed below the barrier voltage. External quantum efficiencies around 1% are estimated with optimized diodes.

ISSN:0003-6951    

DOI:10.1063/1.88358

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Using molecular hydrogen as a model system, we present the first calculation which demonstrates the feasibility of efficient third‐harmonic and sum‐frequency generation of ir laser radiation by diatomic molecular gases. A conversion efficiency of 10% without phase matching is achievable with a modest laser intensity of about 20 MW/cm2. In addition to a two‐photon resonance, the efficient conversion depends on a mechanism which makes use of virtual vibronic transitions exclusively. Possible methods for phase matching are also suggested.

ISSN:0003-6951    

DOI:10.1063/1.88359

出版商:AIP    

年代:1975

数据来源: AIP