摘要:

Both diffused and alloyed junctions were prepared from single crystals of GaP cut from ingots grown near the melting point, as well as from crystals grown at lower temperatures. The diodes were characterized by their current‐voltage relationship and their capacity at reverse bias. Anomalies in both the forward and the reverse currents, an excess capacity, and a hysteresis effect are attributed to the presence of deep centers in the depletion layer, particularly in the alloyed structures. A nearly compensated layer was found at the junction of the diffused diodes. The spectra, bias dependences, decay times, and efficiences of the electro‐luminescence emitted at these junctions at both forward and reverse bias were studied and correlated with the diode models. At reverse bias, radiative intraband relaxation was due to carriers excited during avalanche breakdown (diffused diodes), by internal field emission (alloyed diodes), and from carriers thermally generated within the depletion layer (all diodes). At forward bias, only the diffused junctions exhibited light emission and this was of two types: (1) a band‐to‐band recombination with phonon cooperation, whose recombination kinetics depended on whether or not the process occurred within the depletion layer, and (2) recombination through a deep level which may be associated perhaps with a vacancy.

ISSN:0021-8979    

DOI:10.1063/1.1736232

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A small‐signal analysis of smooth electron beams with periodic variations in their dc parameters reveals the existence of infinite sets of space harmonics of the fast and slow space‐charge waves. For a finite beam coupling between the space‐charge waves and field waves exists at an infinite number of frequencies. The periodicity of a beam has a very small effect on the space‐charge wave propagation constants. Velocity‐jump, rippled‐stream, and rippled‐wall amplification are shown to result from coupling between fast and slow space‐charge waves of adjacent harmonics. The periodicity of an electron beam will have negligible effect on most conventional traveling‐wave devices. Although the frequency dependence of the amplitudes of the beam harmonics may introduce difficulties in some devices, this dependency may also be made use of in a variety of ways. Beam harmonics make millimeter‐wave interactions possible in smooth circuits, but practical devices at these frequencies will probably be limited to those employing positional periodicity of the beam.

ISSN:0021-8979    

DOI:10.1063/1.1736233

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

On anodic polarization of etched samples ofn‐type or near‐intrinsicp‐type germanium, striations are formed. The periodic depletion of holes is advanced as a tentative explanation of the phenomenon.

ISSN:0021-8979    

DOI:10.1063/1.1736234

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A method is proposed for determining the thermal diffusivity &agr; of a thin solid plate, mounted in a vacuum and heated to incandescence by means of a high‐energy electron beam impinging on one face of the plate, or heated by thermal radiation from an arc‐imaging furnace. The beam energy is to be modulated by either a square wave or a sine wave, and the resulting temperature modulation of the faces is to be observed photoelectrically. A theoretical study is made of the possibility of deducing the thermal diffusivity of the solid from amplitude and/or phase measurements. The most practical method seems to be that which involves sine wave modulation, and measurement of the phase difference between the temperatures of the two faces of the plate. With a plate thickness of about 1 mm and frequencies of the order of 0.01–300 cps (depending on the value of &agr;), it should be possible to measure thermal diffusivities, especially of the poorer conductors (&agr; less than about 0.1 cm2/sec), for temperatures from 1000°K or less to the point where sublimation becomes troublesome.

ISSN:0021-8979    

DOI:10.1063/1.1736235

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A physical and mathematical description of maser oscillator is given with particular emphasis upon explaining the structure of the output line shape. Several approaches to the problem are taken. A qualitative description of the motion of the spin vector is followed by a derivation of the equations pertinent to the interaction of a tuned circuit (microwave cavity) and precessing spins. The resultant equation is nonlinear. Approximate solutions are given and these are plotted as output amplitude vs time. In addition, the equations are solved with numerical solutions for specific experimental conditions by means of a digital computer. The numerical results are compared with experimental data including that taken in our laboratory. The field‐swept oscillator line shapes are explained by the analysis, and the steady state oscillator is described as well.

ISSN:0021-8979    

DOI:10.1063/1.1736236

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An analysis of the spectral response of a solar cell is given which includes the effect of the electric field present in the diffused surface region. Results are presented which show the variation of response with junction depth and with carrier lifetime in both surface and bulk regions. By curve fitting, it is found that in a typical silicon cell the bulk lifetime is in the range 1–15 &mgr;sec, while the surface region lifetime is between 10−9and 10−10sec. Bombardment with a total flux of 3.3×1014electrons/cm2of 2‐Mev electrons reduced thenregion lifetime by a factor of 300, and thepregion lifetime by a factor of 6 in a particular case.

ISSN:0021-8979    

DOI:10.1063/1.1736237

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The lattice‐constant and density method revealed that a high‐purity silicon crystal free of dislocations has a perfect lattice without an excess of vacant sites or interstitials (n′=8.00004) within the limits of error, in agreement with the results obtained with the decoration method. The lattice constant of vacuum heated silicon powder of semiconductor purity was 5.43070±0.00004 A; that of the nonheat‐treated powder was 5.43081 A at 25°C. The constants determined from crystal chips by the rotating crystal method were lower: between 5.43028–5.43048 A at 25°C. As the constants of each series of measurements could be reproduced very well (s=±0.00004 A), the lower values suggested the presence of some unknown systematic errors, the magnitude of which is outside the scope of errors due to absorption. The thermal expansion coefficients of all samples between 10°–60°C were (2.6±0.4)×10−6/°C. The average density of etched crystal chips was 2.3289±0.0001 g/cm3. The lower density of the nonetched chips indicated the presence of microcracks, removable by etching, within the distorted surface layers. There was no significant difference in density of bars sawed, or of chips broken from the crystal and etched.

ISSN:0021-8979    

DOI:10.1063/1.1736238

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The Fourier series for the charge density on a hollow tube of finite length is found in such a way that the Fourier coefficients are the unknowns of a system of linear equations. A machine method is used to solve the set of equations in finite order. The leading coefficient is the most accurately known at any order, and solely determines the capacitance of the tube. Capacitances are determined for various ratios of half‐length to radius to an accuracy of better than 0.02%. The technique of solving the integral equation for charge density is useful in other physical problems.

ISSN:0021-8979    

DOI:10.1063/1.1736239

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

In order to obtain an estimate of the maximum piezoelectric polarization possible for alpha quartz, the principal piezoelectric coefficient is calculated on the basis of a hard‐sphere, rigid‐ion model. The result, obtained by purely geometrical reasoning (including anad hocgeometrical constraint), fits the measured value ofe11with an ``effective ionic charge'' of one‐sixth the free ionic charge. Extension of the calculation to finite compressive strain yields a maximum polarization of 3.4 &mgr;coul/cm2at a 34% strain. (Compare withe11=16.7 &mgr;coul/cm2per unit strain.) For higher strains the polarization drops off rapidly, but the model becomes inconsistent for strains greater than 43%. A test for more general validity of the model, by obtaining directly the ratio of the two independent piezoelectric coefficients,e14/e11, yields seven times the measured ratio.

ISSN:0021-8979    

DOI:10.1063/1.1736240

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The rolling texture of high‐purity silver is found to change gradually from the commonsilver typeto thecopper typeas the temperature of deformation increases. The transition is completed in the temperature range 150°–200°C. There is a general correlation between the texture transition and the change in stacking fault frequency as a function of rolling temperature. On the basis of such a correlation, the texture transition produced by varying the temperature of deformation, or by alloy additions, can be consistently interpreted in terms of a change in the stacking fault energy, a change in the dislocation density, or both.

ISSN:0021-8979    

DOI:10.1063/1.1736241

出版商:AIP    

年代:1961

数据来源: AIP