摘要:

Al&sngbnd;Al2O3&sngbnd;Ge tunnel junctions were prepared to study electron tunneling into amorphous germanium films. An almost symmetric conductance minimum centered at zero bias without additional structure was observed. The change in conductance from 1V to zero bias is 103at 78°K and about 102at 300°K. The zero bias conductance is 102times lower at 78°K than at 300°K. The results indicate a large density of states in the gap or near the surface.

ISSN:0003-6951    

DOI:10.1063/1.1653131

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The transition between the two possible pulse train outputs of a mode‐locked laser was studied. The experimental results are in close agreement with a simple, phenomenological model of the transition.

ISSN:0003-6951    

DOI:10.1063/1.1653132

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A standard Polaroid film was proved to be applicable to a quick and easy direct mapping of an acoustic field. The method utilizes the effect of an acoustic field on the developing process of a uniformly pre‐exposed Polaroid film. The method would be most useful for visualization of acoustic field as well as preparing acoustic holograms.

ISSN:0003-6951    

DOI:10.1063/1.1653133

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Data (77°K) are presented showing a dynamic Burstein shift of the absorption edge during spontaneous and laser operation of GaAs:Ge platelets. This is indicated directly by an increase in the relative transmission of the pump power through the sample with increased pump excitation. By the use of pumps with photon energies (1.527 eV) closely matched to the GaAs absorption edge (1. 513 eV), changes in the relative transmission of from 4 to 30% have been achieved. The data presented also show a change in the rate of decrease of the absorption with the onset of stimulated emission by the platelet.

ISSN:0003-6951    

DOI:10.1063/1.1653134

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Self‐induced intensity pulsations of continously operating GaAs junction lasers have been frequency‐stabilized and narrowed by regenerative feedback of oscillations in the injection current. The spectral width of the pulse rate has been reduced by a factor of 20 to less than 30 kHz while the optical pulse width was reduced by at least a factor of 2 to less than 180 psec. These results suggest that a well‐stabilized source of short optical pulses can be constructed from GaAs injection lasers without external microwave circuitry.

ISSN:0003-6951    

DOI:10.1063/1.1653135

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The transit time of high current beams of relativistic electrons (40–50 kA, 350 keV) through an air filled (0.2–2.5 Torr) drift tube has been measured. It is longer than expected, even allowing for the loss of beam front electrons and for orbiting of the electrons in the beam self‐magnetic field. Also, a pressure‐dependent nonuniformity in the beam motion was observed which may account for this delay.

ISSN:0003-6951    

DOI:10.1063/1.1653136

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Dislocation‐free silicon crystals made by the floating zone technique contain vacancy clusters formed during cooling of the crystal after growth. The distribution and concentration of these defects have been determined. A model is presented describing the formation of these clusters. The influence of vacancy clusters on the leakage current of planar diodes is investigated.

ISSN:0003-6951    

DOI:10.1063/1.1653111

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A useful method of calculating the energy/unit depth deposited in atomic processes by energetic ions in solids is presented. The calculated energy density is shown to correlate well with previous Monte Carlo calculations of the vacancy concentration resulting from ion bombardment and recent experimental measurements of the depth distribution of ion damage. The method also provides the depth distribution of ions in the solid as a function of their energy during the stopping process. This information would allow, for example, calculation of the location and rate of various energy‐dependent interactions between incident ions and host atoms.

ISSN:0003-6951    

DOI:10.1063/1.1653112

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The integral depth distribution for divacancies produced in silicon at room temperature by 400‐keV O+ion implantation has been measured. The divacancy distribution was determined from repeated measurements of the characteristic 1. 8&mgr; absorption band following successive anodizations and strippings of the implanted layer. Most of the divacancies are located between 4500 and 12 000 Å with a half‐value at ∼ 7500 Å and a concentration of ∼ 4 × 1019cm−3near the center of the distribution. The measured integral depth distribution for the ion‐produced divacancies is proportional within experimental error to theoretical calculations by Brice for the integral depth distribution of ion energy spent in atomic processes.

ISSN:0003-6951    

DOI:10.1063/1.1653113

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The depth distribution of Si‐P3 centers in 400‐keV O+ion‐implanted silicon was determined using EPR measurements in conjunction with anodization and stripping of the implanted layer. The depth distribution of the EPR centers compares favorably to theoretical calculations by Brice for the depth distribution of the energy deposited into atomic processes and with infrared absorption measurements of the depth distribution of divacancies by Stein, Vook, and Borders. The combined EPR and infrared measurements indicate that the Fermi level in the damaged layer lies betweenEc− 0.21 eV andEv+ 0.25 eV.

ISSN:0003-6951    

DOI:10.1063/1.1653114

出版商:AIP    

年代:1970

数据来源: AIP