摘要:

A complete experimental and theoretical account is given of the eigenmodes (cold and hot) which exist at low power in a cavity partially filled with a plasma. The cavity modes which are perturbed by the plasma together with the basic cold‐plasma modes are studied theoretically using uniform cold‐plasma theory. The hot‐plasma modes of the system are investigated on the basis of a WKB approximation of the relevant equations of a nonuniform hot plasma. Experiments performed with a spherical discharge tube and also with a spherical afterglow plasma give results which are in satisfactory agreement with theoretical predictions. The measuredQfactor of the resonances also agrees with theoretical calculations.

ISSN:0021-8979    

DOI:10.1063/1.1657976

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

It is demonstrated that the conductivity type of organic semiconductors can be modfied by a mechanism analogous to impurity doping. That is, by suitable choice and control of additives, a given organic host may be rendered eithernorptype. Moreover, it is shown that diffusion doping can be employed to formp‐njunctions in a variety of organic host materials. Two examples are discussed in detail to demonstrate the feasibility of doping. First,p‐type tetrathiotetracene (TTT) is shown to becomentype on addition of orthochloronil (OC). The apparent cause is the formation of TTT/OC charge transfer complex molecules within the bulk of the TTT host. Secondly, the normallyn‐type TTT/OC charge transfer complex is shown to become either increasinglyntype orptype on introduction of metal additives.n‐type conduction is achieved with group I and IV metal additives andp‐type conduction with group II and III metal additives. It is also shown that the additives have a significant effect on the conductivity and the activation energy of conduction. Moreover, the changes in the conductivity of TTT, induced by OC additives, are indicative of a tunneling type conduction mechanism. In contrast, the effects due to metal additives can be described by a simple band model. All experiments were performed with compressed powder pellets and the pellet preparation pressure is shown to have a systematic, residual effect on the material properties. The applicability of the doping technique for the preparation of organicp‐njunction diodes is demonstrated by diffusion doping of TTT with OC, TTT/OC complex with Ag and Mg, Perylene with Br, and tetracyano‐quinedymethanol‐quinolinium (TCNQ/QUIN) complex with Ag. Rectification ratios of up to 200 were recorded using, in all cases, compressed powder diodes.

ISSN:0021-8979    

DOI:10.1063/1.1657977

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

This paper reports a direct determination of the relative, static permittivity of the atomic lattice of InSb at 77°K. The measurements were performed on relatively pure (ND≤1014cm−3)n‐type single‐crystal samples at 70.1 GHz by utilizing a strong magnetic field (∼40 kG) to immobilize the charge carriers in a direction parallel to the applied TE01°‐mode electric field. In this manner, the rf losses normally associated with ``drift'' motion of the charge carriers were made negligible, thus permitting the lattice component of the permittivity to be accurately resolved. The measured relative value, &egr;s=17.78±0.15, compares favorably with several values previously calculated from measurements of the ir reststrahlen spectrum.

ISSN:0021-8979    

DOI:10.1063/1.1657978

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A quenching of the exciton‐related blue‐edge photoluminescence was observed in high‐purity single crystals of CdS at their electrical breakdown at 4.2°K. The ionization or destruction of the exciton structures by the carriers in breakdown appeared to be an adequate explanation of this quenching. A differential negative resistance was also seen at breakdown and in some crystals after breakdown as well. This negative resistance was also studied in an attempt to understand the origin of the carriers in breakdown.

ISSN:0021-8979    

DOI:10.1063/1.1657979

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The reverse current‐voltage characteristics of epitaxial SiCp‐njunctions were investigated. After electrolytic etching the junctions showed sharp breakdown. The largest value found for the maximum field at breakdown is 5×106V/cm. Microplasma pulses were observed analogous to but three orders‐of‐magnitude smaller than those hitherto reported for other materials.

ISSN:0021-8979    

DOI:10.1063/1.1657980

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Strong radiative recombination with 0.49 eV energy at 77°K is found in Ge containing Sn. It is proposed that this radiation is due to excitons bound to an isoelectronic Sn center.

ISSN:0021-8979    

DOI:10.1063/1.1657981

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Injection electroluminescence from diffused diodes of gallium‐aluminum arsenide has been investigated. These diodes were prepared from material deposited epitaxially from the liquid state onto oriented gallium arsenide substrates. Diffused diodes emitting radiation at wavelengths as short as 7150 Å have been prepared from material estimated to contain 0.28 mole fraction of AlAs. Microscopic examination has shown that the recombination radiation originates within approximately 1 &mgr; of the junction region. Data on measurements of wavelength and efficiency vs aluminum melt concentration are presented. On the basis of the measured emission wavelengths, the mole fractions of AlAs in the deposited gallium‐aluminum arsenide layers are given.

ISSN:0021-8979    

DOI:10.1063/1.1657982

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Field‐electron microscopy and low‐energy‐electron diffraction can be used in a complementary manner. A method of making such a direct combination on a single specimen is described and applied to a study of the problem of carbon contamination of tungsten surfaces. It is shown that, within the sensitivity of the apparatus used, carbon may be present and remain undetected by the display mode of LEED on a (nonperfect) (011)‐oriented W LEED specimen.

ISSN:0021-8979    

DOI:10.1063/1.1657983

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Ultramicrotomed foils of Cu and Cu‐5 at.% Ge were annealed in the electron microscope. Nucleation and growth of recrystallized grains were observed and their orientations determined. It was found that the fastest growing grains had an orientation relationship with the deformed lattice, which could be described in terms of high‐order {114} twins.

ISSN:0021-8979    

DOI:10.1063/1.1657984

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Hall‐effect measurements are presented for oxidized and unoxidizedp‐type silicon‐on‐sapphire films in the temperature range 77° to 300°K. These measurements show that the dominant scattering mechanism in this temperature range is phonon scattering. The measurements on oxidized films have demonstrated that the mechanism responsible for the observed reduction in acceptor concentration with oxidation is diffusion and preferential redistribution of aluminum from the silicon into the silicon dioxide layer. An additional effect of the oxidation, mobility degradation, is identified as the introduction of scattering centers by the precipitation of neutral aluminum‐oxygen complexes.

ISSN:0021-8979    

DOI:10.1063/1.1657985

出版商:AIP    

年代:1969

数据来源: AIP