摘要:

The Sb incorporation probability in homoepitaxial Si(001) films grown by ultrahigh vacuum ion‐beam sputter deposition at temperaturesTsbetween 100 and 300 °C was found, using quantitative secondary ion mass spectrometry, to be unity with no evidence of surface segregation. Surface roughnesses and epitaxial thicknessestewere measured by atomic force microscopy and cross‐sectional transmission electron microscopy, respectively, for both undoped and Sb‐doped Si layers. Sb doping was found to dramatically increase the rate of surface roughening and to decreaseteby a factor of ≳2 at growth temperatures between 250 and 300 °C while having no measurable effect at lower temperatures. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114607

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

From the velocity of sound measurements, obtained using Brillouin scattering and ultrasound techniques, the elastic and piezoelectric coefficients of lithium triborate (LiB3O5; LBO) single crystals have been determined. Based upon the sound propagation equations and above results, the slowness curves in (100), (010), and (001) crystalline planes are calculated and presented. Some properties of sound propagation and electromechanical coupling in the crystal are also discussed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114608

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Thermally stable, low‐resistance PdGe‐based ohmic contacts to high–low dopedn‐GaAs have been developed. The lowest contact resistance obtained is two times lower than that of previously reported PdGe ohmic contacts. The contacts are thermally stable even after isothermal annealing for 5 h at 400 °C under atmosphere ambient. X‐ray diffraction results and Auger depth profiles show that the good PdGe‐based ohmic contact is due to the formation of both AuGa and TiO compounds. The AuGa compound enhances the creation of more Ga vacancies, followed by the incorporation of Ge into Ga vacancies, and the TiO compound suppresses As outdiffusion from the GaAs substrate, respectively. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114609

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The SrTiO3ultrathin film capacitors were realized on Nb‐doped single‐crystal SrTiO3substrates by chemical vapor deposition. The leakage current density of 10.4 nm thick SrTiO3thin‐film capacitor was below 1×10−8A/cm2in the applied voltage range of −1.8 to +0.45 V, and its SiO2equivalent thickness was 0.48 nm. The relative dielectric constant was over 160 for SrTiO3thickness above 20 nm, but it decreased for SrTiO3thickness below 20 nm. Dependence of leakage current on SrTiO3film thickness was slight. These results could be explained by the existence of applied electric field concentration near the SrTiO3/electrode interface. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114610

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Transmission electron microscopy studies of the (1−x)Pb(Mg1/3Nb2/3)O3–(x)PbTiO3[PMN‐PT (1‐x)/x] crystalline solution have been performed forx=0.1, 0.2, 0.35, and 0.60. Bright‐field imaging has revealed a common sequence of domainlike states with increasingx. Normal micron‐sized ferroelectric domains were found forx≳0.40. Tweedlike structures were found forx∼0.35. These tweedlike structures are similar to those previously reported in premartensitic states. Paraelectric clusters were found forx<0.30. The paraelectric cluster state was characterized by the lack of self‐assembly amongst embryos and the presence of relaxor behavior in the macroscopic response characteristics. The composition PMN‐PT 65/35 was then modified with La for a detailed study of the transition between the tweedlike precursor and paraelectric cluster states with increasing impurity content. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114611

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Infrared polarization spectroscopy of the stretching motion of physisorbed CO2has been used as a probe for the heterogeneity of hydrogen‐terminated diamond single crystal surfaces. At the substrate temperature of 83 K, band shape, photometry, and isotherm measurements all indicate that the CO2molecules are first adsorbed on defect sites, followed by adsorption on terraces that yields a single sharp spectral feature at 2333 cm−1with FWHM=6 cm−1. Nearly 20% of the surface sites on the as‐polished C(111)‐1×1:H surfaces are defects ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114612

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Chemical vapor deposition using 2‐methyl‐1,2′‐naphthyl ketone as a starting material has been done between 1000 and 600 °C on Ni particles with diameters ranging from 10 to 500 nm. The Ni particles were prepared by annealing Ni thin film deposited on quartz glass substrates. The size of the Ni particle was controlled by the thickness of the Ni film. Carbon nanotubes were obtained at 700 °C when the diameter of the Ni particles was about 20–30 nm. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114613

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We have observed nonorthogonal twinning in thin film oxide perovskites. This twinning geometry is equivalent to a 60° rotation of the twinned crystallites about the [111] direction in an [001] oriented film. This twinning is not detectable by the standard x‐ray tests for film quality (a radial &thgr;–2&thgr; scan and a &fgr; scan at a chi of 45°). In this study we observe this twinning in films of PbZrxTi1−xO3, BaTiO3, and SrRuO3grown by sputtering and MOCVD on MgO and SrTiO3. These twins are observed in films deposited on a substrate with which there is a large lattice mismatch and in films that are deposited in an oxygen deficient environment. We propose that these twins result from plastic deformation associated with misfit accommodation and discuss the twin geometry and the nature of the twin interface. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114614

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Raman spectroscopy in conjunction with near‐field scanning optical microscopy is used to image Rb‐doped KTiOPO4within a spectral feature with high spatial resolution. We present Raman spectra as well as the first Raman images obtained in the near field. Differences between near‐field and far‐field Raman measurements are discovered and discussed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114615

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Highly elastically strained films of InGaAsP solid solutions in 1.4–1.8 eV interval of band gaps were grown on GaAs(111)B substrates by liquid phase epitaxy. Elastic strains close to 1% are achieved. The determined critical thicknesses exceed the predictions of the energy equilibrium theory by Matthews and Blakeslee by as much as an order of magnitude. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114616

出版商:AIP    

年代:1995

数据来源: AIP