摘要:

We present a novel principle for a fast bistable nematic display with intrinsic grey scale. The geometry of a single pixel is the usual hybrid texture in between two conductive flat plates. The device is written by creating surface walls when an electric field is applied, above the thresholds to achieve both the planar anchoring breaking and an electro-hydrodynamic flow. Erasing is obtained by simply breaking the anchoring in absence of vortices. The distorted regions around surface walls depolarize the incident light. As the surface defect density can be modulated, a grey scale is achieved. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120370

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

With the use of first principles theory we confirm the semiconducting ground state of the technologically interestingYH3compound. Thus, unlike previously published theories, we demonstrate that density functional theory in the local density approximation reproduces the existence of a band gap. We also show that theHoD3structure is the stable structure at ambient conditions, in agreement with experiment. In addition, we predict that moderate applied pressure will driveYH3into the cubic structure. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120371

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report transmission electron microscopy (TEM) studies of precipitation in Ag-implanted and annealedAl0.3Ga0.7As.Silver was chosen because it does not form compounds with Ga and/or As when precipitating based on bulk thermodynamics arguments. TEM confirmed the formation of an elemental metal/semiconductor composite, which consists of nanometer-sized Ag (fcc structure) precipitates dispersed in the matrix. The precipitates are nonspherical and have an orientation relationship toAl0.3Ga0.7Asof (200)Ag//(200)AlGaAs, (02-2)Ag//(02-2)AlGaAs, and [011]Ag//[011]AlGaAs. High temperature (900 °C) anneals transform the phase of the precipitate to hexagonal,Ag3(GaAl)compounds. This shape distribution has been correlated with inhomogeneous broadening of the optical absorption. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120372

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

In the transition layer of the Si(001)–SiO2interface, Si lattice strain and its distribution were directly observed by medium energy ion scattering spectroscopy for thermal and ion beam oxides. The strain was in the vertical direction, and the maximum values at theSiO2side of the transition layer were 0.96&percent; and 2.8&percent; for the thermal and ion beam oxides, respectively. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120373

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have proposed aPt/SrBi2Ta2O9/CeO2/SiO2/Sistructure for a ferroelectric gate of metal ferroelectric insulator field effect transistor. A memory window of the proposed ferroelectric gate increases as electric field applied to theSrBi2Ta2O9layer increases, and the memory window ofPt/SrBi2Ta2O9/CeO2/SiO2/Siis relatively greater than that ofPt/SrBi2Ta2O9/SiO2/Si.As a result, thePt/SrBi2Ta2O9(140 nm)/CeO2(25 nm)/SiO2/Sistructure has sufficiently programmable memory windows from 0.9 to 2.5 V in the low gate voltage range of 4–7 V. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120374

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have grown thin Ge films that were fully strain relaxed and had smooth surfaces on Si(001) surfaces without buffer layers by ultrahigh vacuum chemical vapor deposition. The procedure consists of layer-by-layer Ge growth with hydrogen-surfactant mediation and high-temperature(∼700 °C)post-growth annealing for strain relaxation. The key step is the formation of a thin (less than 1 nm thick) capping Si or SiGe layer on the layered Ge film before the annealing. This capping layer effectively suppresses clustering of Ge during the annealing, even at high temperatures. Cross-sectional transmission electron microscopy of annealed samples having a 20-nm-thick Ge film clearly revealed a periodic array of 90° full-edge dislocations with a Burgers vector ofa/2⟨110⟩type confined at the Ge/Si interface. This dislocation structure leads to efficient strain relaxation in the Ge film, which was also confirmed by x-ray diffraction measurement. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120375

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have developed a method of imaging at high temperatures with atomic force microscopy using a laser to deliver heat to an area localized around the AFM tip–sample junction. We couple approximately 75 mW from an argon-ion laser into the active region to raise the temperature of a 100 nm gold film to around 225 °C. As a sample, we use 1.2 &mgr;m polystyrene spheres adsorbed onto the film. We image the flow of these spheres,in situ, over the course of an hour. The dynamics of the polymer spreading is shown to be consistent with the dry spreading of a precursor film. ©1997 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.120376

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report that the sign of the polarization of an epitaxial ferroelectric film can be determined from the interference between the x-ray scattering from the film and the substrate. X-ray scattering measurements of a 10 nm epitaxialPbTiO3film grown by metal-organic chemical vapor deposition on aSrTiO3substrate are presented. The scattering profile near the001peaks of the film and substrate shows clear evidence of the interference effects. Analysis indicates that this film is a single domain of specific polarity. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120377

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A simple theory is formulated in which the pressure of bubbles containing hydrogen molecules in the implanted region drives exfoliation due to the anisotropy of the elastic forces and the evaporation or slow diffusion of atomic hydrogen to molecular hydrogen in the bubbles leading to a catastrophic growth in the bubble radius and the molecular fraction as temperature increases. The process of blistering and cratering at small implant depths is also considered. Comparison to recent experiments is made. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120378

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A growth mechanism for BN nanotubes appearing at superhigh pressures under laser beam heating [D. Golberg, Y. Bando, M. Eremets, K. Takemura, K. Kurashima, and H. Yusa, Appl. Phys. Lett.69, 2045 (1996)] is proposed based upon consideration of the dependence of the energy of adsorption and surface diffusion on the surface curvature. According to this mechanism, the growth of BN nanotubes is due to surface diffusion along the external surface, which also ensures morphological stability of the open end during growth. It is suggested that the observed nanotube heights are limited by the corresponding diffusion length. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120379

出版商:AIP    

年代:1997

数据来源: AIP