摘要:

The removal of the adsorbed gases and the surface oxide on single‐crystal, 100 &OHgr;‐cm silicon filaments by ion bombardment and annealing does not have an appreciable effect on either the magnitude or the frequency dependence of the 1/fnoise from the filament. Since the slow surface states are commonly associated with gases adsorbed on the oxide, charge transfer between these states and the bulk cannot be the primary source of 1/fnoise in semiconductors. The changes in the 1/fnoise that were observed during the surface cleaning procedure can be correlated with the presence or absence of an inversion layer at the surface.

ISSN:0021-8979    

DOI:10.1063/1.1729021

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The thermal radiation of lossy media is described by a random current‐source term that is introduced into Maxwell's equations. The media treated are linear, in general anisotropic, nonuniform, and such that the constituent relations are not local relations, but are described in terms of a Green's operator. For such media, in thermodynamic equilibrium, it is shown that simple relations exist between the correlation and spectral density matrices of the random current‐source field and the Green's conductivity operator. These relations are analogous to Nyquist's theorem of lumped circuits.

ISSN:0021-8979    

DOI:10.1063/1.1729022

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Two types of etch pits in cadmium telluride have been observed. The etchants used are nitric acid solutions of potassium bichromate which also contain silver ions of various concentrations. The etch pits resulting from etch (EAg‐1) grow into a tetrahedral shape bounded by the crystallographic habit planes and reveal geometrical polarity on the (111) and (1¯1¯1¯) surfaces. Another type of etch pit is formed at a different point from that of the pit with EAg‐1 by the modified etch (EAg‐2), which has increased content of Ag+ion. The two types of etch pits, with EAg‐1 and with EAg‐2, are believed to be associated with Cd and Te edge dislocations. The dissolution rate and its selectivity to the constituent elements in cadmium telluride is controlled electrochemically by the variation of the Ag+ion concentration of the etching solution. The structure of the twin boundary is also studied by etching and back Laue techniques.

ISSN:0021-8979    

DOI:10.1063/1.1729023

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The rf noise power spectrum at a Langmuir probe in a cold‐cathode neon discharge is observed over a 50‐kc to 10‐Mc range. The statistical noise amplitude distribution function is found to be Gaussian and the probe noise can be analyzed in terms of shot noise of the probe electron and ion currents using a substantially constant probe sheath impedance at different probe potentials. The noise current spectral density increases at low frequencies in agreement with hot‐cathode discharge probe observations, has a minimum at about the shot noise current level, and has a high‐frequency increase corresponding to that observed by Shimada [K. Shimada, Proc. I.R.E.49, 632 (1961)]. It is believed that freedom from wall effects can be attained, since relative insensitivity of the noise to discharge pressure, current, and purity is observed. The introduction of stationary striations does not influence the power spectrum other than to superimpose very sharp oscillatory peaks which are easily altered by changing discharge current or pressure. Low‐frequency fluctuations in the plasma can be largely eliminated by using large diameter discharge tubes.

ISSN:0021-8979    

DOI:10.1063/1.1729024

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The increase in dielectric constant and losses during switching was measured in barium titanate and triglycine sulfate (TGS) at frequencies up to 2 Gc. These measurements revealed the presence of two relaxations, one at low frequencies (described by Landauer, Young, and Drougard) and a new one at higher frequencies. The relaxation frequency of this new relaxation is 100 Mc in the case of triglycine sulfate and higher than 2 Gc in the case of BaTiO3. The value of &Dgr;&egr;′ at the relaxation frequency is 2 for triglycine sulfate and 1.2 for BaTiO3.A model which explains the experimental facts is given. The increase in dielectric constant and losses is attributed to oscillations of the ``side'' walls of the ferroelectric domains in the case of the high frequency relaxation. The low‐frequency relaxation is believed to be due to oscillations of ``front'' walls of the newly formed domains.

ISSN:0021-8979    

DOI:10.1063/1.1729025

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The diffusion of vacancies in Ge and Si during quenching from the melting point is examined mathematically. In typical dendrites of either material (0.01‐cm‐thick ribbons), cooling after growth is slow enough so that only 10−3of the concentration of vacancies at the melting point &phgr;0can be trapped. For this calculation vacancies are considered as the only defects present, and surfaces are considered as the only vacancy sinks. For Ge samples of larger dimensions (approximately 0.1 cm) cooled by radiation alone the concentration trapped can be34[open phi]0with surfaces acting as the only sinks. However, if dislocations in excess of 104per cm2are present acting as vacancy sinks of 10−7‐cm radius, the concentration quenched‐in drops very rapidly with increasing dislocation density. At 105per cm2only 10−2&phgr;0are quenched‐in. Thus, if samples contain more than 105dislocations per cm2, vacancies would probably not be observed in radiation quenching experiments. Existing theory combined with the present calculation indicates that the formation of dislocation loops in growing Ge dendrites is unlikely.

ISSN:0021-8979    

DOI:10.1063/1.1729026

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

This paper describes the properties of surface‐barrier photocells on silicon. In particular, data are given on photocurrent versus light intensity, photocurrent versus reverse bias voltage, open‐circuit photovoltage versus light intensity, open‐circuit photovoltage versus wavelength of light, open‐circuit photovoltage versus temperature, and photocurrent versus temperature. An interesting multiplication effect of optically excited carriers is observed at lower temperatures. The theory of the surface‐barrier photoeffect is further generalized.

ISSN:0021-8979    

DOI:10.1063/1.1729027

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The overshoot in the photoconductivity of lead oxide has been studied. It has been concluded to be due to build‐up of space charge in the bulk of the material, rather than to any blocking at the electrode. The overshoot vanishes both at temperatures above +70°C and below −50°C. A physical model, which can explain these results, has been discussed.

ISSN:0021-8979    

DOI:10.1063/1.1729028

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Thin films of lithium when evaporated onto well‐polished, chemically cleaned, and outgassed Ta and Pt substrates formed uniformly thick layers (in the range 240–1600 Å) suitable for thep‐nreaction in the Van de Graaff generator. A thin carbon coating, (about 300 Å thick) evaporated upon the Li film from a heated carbon filament immediately following the deposition of lithium on Ta and Pt substrates, insulated chemically the lithium from the air with its water vapor content and also provided carbon replicas of the Li films surface for electron microscopy.Proton bombardment of the carbon‐coated Li films had no visible effect on the carbon coating nor on the Ta or Pt substrate. However, after a proton beam bombardment of 10 &mgr;A‐min at 1.88 MeV, the Li films gave evidence of some initial damage effect (growth of grain size plus surface unevenness) which appeared to anneal away with subsequent bombardment.Orientation effects were observed in Li films deposited upon carbon substrates (in turn deposited on nickel lectromesh grids) in a special evaporator, attached to and forming a part of the vacuum system of the electron microscope (RCA type EMU‐2B) in order to avoid contamination of the Li with the laboratory atmosphere. Electron diffraction patterns revealed the following: (1) random orientation for the thinner (240 Å, approximately) Li films and (2) preferred orientation of the (110) and (200) planes nearly perpendicular to the surface for the thicker (1600 Å, approximately) films.

ISSN:0021-8979    

DOI:10.1063/1.1729029

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

When an em (electromagnetic) wave of fixed frequency is incident on the cylindrical positive column of a low‐pressure mercury vapor arc discharge with its electric field and direction of propagation both perpendicular to the column axis, a spectrum of resonances of reflection and transmission occurs as the discharge current of the positive column is varied. In addition to the expected cylindrical plasma resonance, a set of lesser resonances may be distinguished. The locations of these resonances have been extensively studied experimentally as functions of temperature and signal frequency for four tubes of different cross sections. It is shown that temperature, which is governed by losses in the plasma column and by the ambient temperature, has a substantial effect on the location of the resonances. By using this effect, spectra of resonances are easily obtained over a frequency range of 4400 to 22 000 Mc for the smallest tube. In addition, the sharpness of the cylindrical plasma resonance is calculated from experimental data and compared with theoretical curves ofQwhich have been determined from equations which take into account radiation and collision damping.

ISSN:0021-8979    

DOI:10.1063/1.1729030

出版商:AIP    

年代:1962

数据来源: AIP