摘要:

Interband transitionsE1andE1+&Dgr;1were investigated using the electrolyte electroreflectance technique for various compositions of InxGa1−xAs layers deposited on GaAs by molecular‐beam epitaxy. A discrepancy in the results for layers deposited with lattice mismatch and bulk materials was noticed. The results were compared with the predictions of the scaled‐virtual‐crystal‐approximation method for transition energy dependence on composition.

ISSN:0021-8979    

DOI:10.1063/1.336875

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Substitution of He3for normal helium in a sealed‐off conventional CO2laser resulted in power output increases as high as 14%. No such effect was observed in a narrow‐bore waveguide laser, indicating that the observed improvements were due to more efficient heat conduction to the tube wall.

ISSN:0021-8979    

DOI:10.1063/1.336876

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The expansion of the shock front of a laser‐triggered, atmospheric air spark was studied by shadow photography with a transversely excited atmospheric UV nitrogen laser. It was found that the shock front of the short spark (0.5 mm) was cylindrical. Within a few nanoseconds of spark formation the diameter of the spark channel grows linearly with time and the index of refraction is less than in the surrounding gas. The shock velocity was measured to be 7 km/s (Mach 20).

ISSN:0021-8979    

DOI:10.1063/1.336823

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We report the first measurements of the linear thermal expansion coefficient &agr;tof hydrogenated amorphous Ge thin films. We have utilized optical reflection interference fringes to measure the gap between the film and a fused quartz substrate in a segment of the film which lifted from the substrate due to intrinsic compressive strain. The linear thermal expansion coefficient of &agr;t=1.7×10−5K−1for 300 K <T< 420 K is ∼3 times larger than that of crystalline Ge.

ISSN:0021-8979    

DOI:10.1063/1.336824

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We report the first epitaxial growth of lanthanum trifluoride on the (111) surface of gallium arsenide. Smooth, crack‐free, and high‐crystalline quality films of thickness up to 200 nm were grown at 500 °C on a GaAs(111) surface that was cleaned by ion heat treatment and post‐anneal. The film surfaces were examinedinsituby low‐energy electron diffraction (LEED) andexsituby reflection high‐energy electron diffraction (RHEED) and Nomarski optical microscopy. Capacitance‐voltage (C‐V) and current‐voltage (I‐V) measurements showed a breakdown strength of 2×106V/cm and no significant flat‐band shift due to insulator charges.

ISSN:0021-8979    

DOI:10.1063/1.336825

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Anderson and Nafe [J. Geophys. Res.70, 3951 (1965)] pointed out that while log K‐log Vplots for a large number of crystals have a slope of −1, the plot for oxide compounds has a slope of −4. Recent data on the bulk modulus of eight oxides with a NaCl structure are examined. It is observed that the log K‐log Vplot for these crystals has a slope of −1 and not −4. From this plot it is estimated that these oxides have an effective ionic charge of about 0.8. The data on lead chalcogenides are also examined. It is shown that from the two widely different values of the bulk modulus of PbSe, the physically acceptable value can be sifted out from the log K‐log Vplot.

ISSN:0021-8979    

DOI:10.1063/1.336826

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

It has been found that by the deposition of a thin layer of LiF on rock‐salt cleavage faces the epitaxial growth of Ag, Al, Cu, Cr, Fe, V, and Mo will be improved markedly. The simultaneous growth of the metals on air‐cleaved rock‐salt substrates and on air‐cleaved rock‐salt faces covered with a LiF interlayer before the metal deposition have been compared by transmission electron microscopy and x‐ray rocking curves.

ISSN:0021-8979    

DOI:10.1063/1.336827

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The eigenvalue problem of whistler propagation in a magnetic trap is analyzed in the slab model. The plasma is comprised of three regions: (I)a≤x<∞, (II) 0≤x≤a, and (III) −∞<x≤0. Region II contains a hot‐electron component and possesses a smaller magnetic field. The hot electrons have a temperature anisotropy and tend to destabilize the whistler mode. The dip in the magnetic field tends to confine the mode to region II.

ISSN:0021-8979    

DOI:10.1063/1.336828

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Prebreakdown electron emission from polished stainless steel and from this surface covered with a 0.2–0.4 &mgr;m coating of CaF2is measured at applied fields from 0.2 to 1.0 MV/cm. The CaF2coating suppresses field emisssion by up to six orders of magnitude. In addition, the CaF2coating increases the standoff voltage by ∼50%.

ISSN:0021-8979    

DOI:10.1063/1.336829

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

High‐low (HL) junctions form part of many semiconductor devices, including back surface field solar cells. A first experimental determination and interpretation of the voltage across the HL junction under low‐ and high‐injection conditions is presented as a function of the voltage across a nearbyp/njunction. Theoretical analysis from first principles is shown to bear well on the experimental results. In addition, a test structure is proposed for measurement of the effective surface recombination velocity at the HL junctions.

ISSN:0021-8979    

DOI:10.1063/1.336830

出版商:AIP    

年代:1986

数据来源: AIP