摘要:

We present a high‐resolution electron microscopy study of the microstructure of boron nitride thin films grown on silicon (100) by radio‐frequency plasma‐assisted chemical vapor deposition using B2H6(1% in H2) and NH3gases. Well‐adhered boron nitride films grown on the grounded electrode show a highly oriented hexagonal structure with thec‐axis parallel to the substrate surface throughout the film, without any interfacial amorphous layer. We ascribed this textured growth to an etching effect of atomic hydrogen present in the gas discharge. In contrast, films grown on the powered electrode, with compressive stress induced by ion bombardment, show a multilayered structure as observed by other authors, composed of an amorphous layer, a hexagonal layer with thec‐axis parallel to the substrate surface and another layer oriented at random. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363677

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Growth by molecular‐beam epitaxy and characterization of Si‐doped and unintentionally doped Ga1−xInxSb layers in the full compositional range on GaAs substrates are reported. The grown samples were characterized by reflection high‐energy electron diffraction, x‐ray diffraction, Hall‐effect measurements, and secondary‐ion‐mass spectroscopy. The unintentionally doped layers had carrier concentrations below 6×1016cm−3with a maximum atx≊ 0.5, where the conduction switched fromptontype. Silicon doping in the 1017cm−3range provided acceptors up tox≊0.85 for a growth temperature of 430 °C. For higherxvalues conduction was mixed and the Hall‐effect data suggest that an inversion layer of electrons could be present on the surface. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363678

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Bulk anisotropic magnets with the composition of Sm2(Fe,M)17CxNy(M=metal) have been produced by conventional powder sintering of the carbide, followed by gas‐solid reaction. The results show that this is a very promising technique for producing high‐performance bulk anisotropic magnets based on intercalated rare‐earth–iron compounds. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363646

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The temperature‐dependent dispersion equation is derived to predict the ordinary and extraordinary refractive indices of lithium tantalate in the region of 0.4–4 &mgr;m and for a temperature range of 25 °C–300 °C. The Sellmeier equation is compared with the measured data. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363679

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Fluorinated nanocrystalline silicon films,nc‐Si:H,F, have been deposited from SiF4–SiH4–H2mixtures by means of the plasma enhanced chemical vapor deposition technique. The presence of fluorine atoms, which are effective etchant species, promotes selective etching giving nanocrystalline films. These materials, with grain size of 100–200 A˚, show a room temperature photoluminescence centered at 1.62 eV. Also, the widening of the optical energy gap (Eg=2.12 eV) is mainly due to the presence of nanocrystals rather than to the H content of 4.5 at. %. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363641

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We analyze the problem of onset of morphological instability and the increasing supersaturation gradient in the particular case of float‐zone traveling solvent growth of LaB6crystals in excess of La, taking into account the actual liquidus line on the relevant phase diagram of Storms and Mueller [J. Phys. Chem.82, 51 (1978)]. We show that the action of Marangoni convection decreases the concentration gradient at the solidification interface and inhibits the morphological instability and the increasing supersaturation gradient. We suggest that this effect allows the implementation of float‐zone traveling solvent growth of LaB6crystals with pulling rates of &bartil;1 cm/h without the appearance of defects structures associated with the morphological instability and increasing supersaturation gradient. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363642

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

In this paper we comment on the interpretation ofCVdata in the presence of deep levels or interfacial layers. In order for the barrier height extracted fromCVmeasurements to be reliable, no frequency dependence should exist at the measurement frequencies, and the slope of the 1/C2vs voltage curve should not be temperature dependent. This is illustrated by data from Schottky barriers on 6H–SiC. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363643

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We reply to the comment by Fro¨jdh and Petersson concerning the measurements of the barrier heights of Schottky diodes on 6H‐SiC. We present the argument that the temperature range over which Fro¨jdh and Petersson present data does not allow accurate comparison with our results. The problem of interaction of deep levels in the capacitance‐voltage measurements is refuted by deep‐level transient spectroscopy data. We conclude that our data are accurate and our methods reliable. ©1996 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.363644

出版商:AIP    

年代:1996

数据来源: AIP