摘要:

New values for the elastic and piezoelectric constants of Bi12GeO20and for their temperature derivatives are reported. With these new constants, the predicted value of &Dgr;v/vfor acoustic surface waves is significantly increased. This prediction has been verified by measurements of the acoustic surface‐wave velocity on the metallized and unmetallized (001) surface of Bi12GeO20and by comparing the observed values with theory. On the (001) plane, the maximum &Dgr;v/voccurs in the ⟨110⟩ direction. The predicted &Dgr;v/vis 66×10−4and the experimentally observed value is (77±15)×10−4.

ISSN:0003-6951    

DOI:10.1063/1.1653397

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The Cs content of GaAs(Cs) and GaAs(Cs&sngbnd;O) photocathodes was determined by direct chemical analysis. The surface films were found to be of monolayer dimension. From this result, it is concluded that the effect of these films on electron emission is probably not associated with the bulk properties of cesium oxide.

ISSN:0003-6951    

DOI:10.1063/1.1653398

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Optical (3–6 eV) reflectivity spectra of Cd+‐implanted layers of GaAs are examined as functions of dose in the range of 1012to 8×1014ions/cm2and of annealing up to 600°C. Characteristic peaks in the crystalline spectrum decrease smoothly with dose, with some saturation observed at about 6×1013/cm2. Annealing tends to partially restore the spectra toward the crystalline form. Similarity with results for implanted silicon layers is noted. Reflectivity and observations of lattice damage by Rutherford scattering are correlated.

ISSN:0003-6951    

DOI:10.1063/1.1653399

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A surface‐wave path containing a fluid interface region which couples Rayleigh waves from one crystal to another is an effective filter for passing Rayleigh waves while rejecting other in‐band spurious modes. Results of tests made on a wide‐band (50% bandwidth) variable delay line (5–15 &mgr;sec) incorporating this fluid interface filter are shown.

ISSN:0003-6951    

DOI:10.1063/1.1653400

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Experimental results are presented giving the operating characteristics of a newly developed DF&sngbnd;CO2purely chemical laser. The present oscillator is capable of a maximum cw output power of 162 W at 10.6 &mgr; with no external energy source used to initiate or sustain laser excitation. An optical axis has been employed aligned transverse to the flow direction with a view toward achieving operation which can be directly scaled to high output powers. Measurements of saturation parameter, unsaturated gain coefficients, and vibration‐rotation state populations forP‐ andR‐branch CO2(00°1) → CO2(10°0) transitions, power output, operating temperatures and pressures, and chemical efficiency are presented.

ISSN:0003-6951    

DOI:10.1063/1.1653401

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Electromigration‐induced failures in aluminum film conductors have been studied. It is shown that large‐grain films have a longer mean time to failure (MTF) than the small‐grain films. A further increase in MTF is observed for films with a glass overcoating. This increase can be understood in terms of the observed grain growth which results from the glass overcoating process. Histograms showing the location of failures are interpreted to indicate that effects due to both temperature gradients and microstructural inhomogeneities are important.

ISSN:0003-6951    

DOI:10.1063/1.1653402

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

It is pointed out that the conventional capacitance method and the Copeland method provide different results for the determination of impurity concentrations of semiconductor wafers in the presence of deep centers. On the basis of a discussion of this phenomenon, a simple method of determining the concentration and the energy level of deep centers is proposed and demonstrated. The method is checked by application to oxygen‐dopedn‐type GaAs with a carrier concentration of 3.2×1015cm−3. The result yields a value of 2.1×1016cm−3for the deep center concentration and a value of 0.57 eV below conduction band for the energy level of the deep centers, which are reasonable in comparison with other experimental data.

ISSN:0003-6951    

DOI:10.1063/1.1653403

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The second harmonic of a ruby laser has been produced in LiIO3crystals, showing hardly any optical absorption at 0.347 &mgr;. Using these new crystals external to the laser cavity conversion efficiencies up to 40% have been achieved using an incident unfocussed beam of about 130 MW/cm2. After 5–10 shots, a first small internal damage spot appeared inside the LiIO3crystal. For a beam diameter of 3 mm several hundred shots with a conversion efficiency of 40% were possible.

ISSN:0003-6951    

DOI:10.1063/1.1653404

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Light‐ultrasound interaction techniques were employed to measure the velocity and absorptivity of surface waves in various directions on the (100) face of single‐crystal copper sample. Schlieren images of beam displacement at the liquid‐sample interface were used to determine crystal orientation.

ISSN:0003-6951    

DOI:10.1063/1.1653405

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Impurity diffusion, using the donor impurity Sb, has been used to prepare high‐quality Pb1−xSnxTe (x=0.13–0.20) light‐emitting diodes. The emission of 8–14 &mgr; spontaneous and laserlike radiation from these diodes is discussed in terms of the optical gain expected at these wavelengths.

ISSN:0003-6951    

DOI:10.1063/1.1653406

出版商:AIP    

年代:1970

数据来源: AIP