摘要:

The spectroscopic method has been used to study sputtering yields under normally incident ion bombardment at very low ion energies. Data have been extrapolated to determine threshold energies for sputtering under normal incidence. These estimated thresholds are approximately the same energy (roughly four times the heat of sublimation) as the displacement thresholds for radiation damage. The mass ratio between ion and target atoms plays hardly any role in the thresholds.

ISSN:0021-8979    

DOI:10.1063/1.1728959

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The motion of lithium in ann‐pjunction under reverse bias is discussed. Expressions are derived for the distribution of lithium in the ``intrinsic'' layer as it depends on time. Results for the width of this layer agree with the earlier calculations of Pell. Information concerning this width simplifies the calculation of the detailed distribution. Thus it is convenient to combine Pell's method with ours to supply an expeditious method for arriving at the distribution. The results of the calculation indicate that the so‐called ``intrinsic'' layer produced by drift under reverse bias should beveryhighly compensated over most of its extent.

ISSN:0021-8979    

DOI:10.1063/1.1728960

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The resistance of semiconducting crystals to indentation deformation has been found to be lowered significantly (up to 60%) by the simultaneous presence of a small potential (0.05 to 10 V) between the indenter and the crystal surface. This electromechanical effect appears to be confined to the plastic strain region of a surface layer of material 2–3 &mgr; deep.A large body of experiments of varied nature have established that the effect is real and not spurious. Similar effects are observed in a number of different semiconductors (Ge, Si, InSb and SiC) but not in metals or ionic crystals. The effect disappears at elevated temperatures but becomes enhanced below room temperature. It is not sensitive to the type of current carrier. The roles of surface preparation, crystallographic orientation, kind and concentration of charge carrier, geometry, and time have also been examined. Other and possibly related experiments show significant enhancement of the surface photovoltage (the Dember potential) by a longitudinal electric field. All of these experiments are extensively documented and discussed but no satisfactory model or mechanism has yet been conceived.

ISSN:0021-8979    

DOI:10.1063/1.1728961

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A N14H3maser based on Ramsey's principle of separated oscillatory fields has been used to increase the resolution over a conventional maser. A single component of the 3.3 inversion line of N14H3can be isolated. This type of maser overcomes the difficulties arising from the composite structure of the line.

ISSN:0021-8979    

DOI:10.1063/1.1728962

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The transient response of a three‐level optical maser is calculated for a density of homogeneously broadened atoms coupled to one homogeneously broadened cavity mode. The atoms are treated in terms of the density matrix and the cavity mode is treated classically. Solutions are found analytically for the steady state and for the linearized form of two simplifications of the general equations. These special solutions have been previously obtained by Bloom and Statz and de Mars. Numerical solutions are found for a certain set of parameters. The response linewidth is found assuming one cavity mode coupled to a density of inhomogeneously broadened atoms.

ISSN:0021-8979    

DOI:10.1063/1.1728963

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A removable ferromagnetic core is used to increase the trapped flux in a multiply‐connected superconductor. This original trapped flux is then compressed by a superconducting piston so as to produce an intense magnetic field within a relatively large volume. Additional experiments are described in which superconducting switches are used to compress the flux in a cyclic manner.

ISSN:0021-8979    

DOI:10.1063/1.1728964

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The variations in the specific surface area of evaporated aluminum due to substrate temperature, film thickness, and angle of incidence have been determined experimentally. Increasing the substrate temperature from 0° to 100°C decreases the specific surface area by a factor as large as 9. Increasing the film thickness from 3000 to 12 000Å increases the specific surface area by a factor as large as 17. The specific surface area increases with increasing angle of incidence and has been observed to change in the range of 1.0 to 25.2. Atomistic models for the growth of rough films from vapor are considered. One model which has been proposed in which asperities grow from islands which form during the initial stages of condensation is rejected on the basis of experiment. A second model in which asperities grow from crystallites having preferred crystallographic orientations is found to be adequate to explain the observations of this and certain other investigations.

ISSN:0021-8979    

DOI:10.1063/1.1728965

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A new discharge is described which is radially contained by a magnetic field and is not sustained by electron emission from any surface. Two positive anodes of arbitrary but similar shape are lined up along the magnetic field. A control electrode, at a lower potential, is placed between them and creates a potential barrier and two positive potential wells in the vicinity of each anode. Electrons are axially trapped in these wells. An rf voltage in the megacycle range is applied, out of phase, to the two anodes and causes the trapped electrons to alternately spill across the barrier and pick up energy from the rf field. During each half‐cycle they make many oscillations in the potential well which is most positive and make ionizing collisions. Every ion pair yields an electron which can gain energy in the same way. The process is very efficient and is characterized by rf breakdown voltages that approach the ionization potential of the gas.

ISSN:0021-8979    

DOI:10.1063/1.1728966

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The magnetic properties of iron particles in mercury with diameters smaller than 500 Å are sensitive to to the adsorption of tin. The intrinsic coercive force and remanence both change on the addition of tin until an amount has been added corresponding to the adsorption of roughly one monolayer. The particle sizes calculated from these adsorption data are consistent with previous size determinations. Diffusion of tin into the iron was not significant at room temperature. The addition of tin to dispersions of cobalt particles in mercury produced changes in magnetic properties related principally to a rapid diffusion of tin into the cobalt.

ISSN:0021-8979    

DOI:10.1063/1.1728967

出版商:AIP    

年代:1962

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1728969

出版商:AIP    

年代:1962

数据来源: AIP