摘要:

Tungsten oxide films were made by magnetron sputtering with a large angle between the substrate normal and the direction of the deposition flux. Scanning electron microscopy displayed a microstructure composed of inclined columns. Spectrophotometric measurements on films with different amounts of electrochemically intercalated Li+ions showed pronounced angular selective transmittance together with electrochromism. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113343

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report the observation of optical control of the stimulated emission of a vertical cavity surface emitting laser (VCSEL) by an intra‐cavity coupled in‐plane laser. Depending on the overlap between the two gain regions, greater than 70% change in threshold current to complete quenching of the VCSEL, is observed. The combined device offers a wide variety of potential applications for integrated, all‐optical logic devices and optical interconnects between signal planes. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113344

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A new experimental technique for the measurement of intrinsic parameters of vertical cavity surface emitting lasers is suggested. Using an external cavity with variable reflectivity we measure the internal quantum efficiency of &eegr;i=0.6 and internal losses of &agr;i=10 cm−1in a gain guided AlGaAs/GaAs laser operating at 850 nm. In addition, transparency current ofI0∼0.46×Ithis obtained, in excellent agreement with a direct measurement. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113345

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Data are presented characterizing threshold and transverse mode behavior of microcavity lasers, which use a half‐wavelength cavity spacer layer surrounding a single quantum well active region. Selective conversion of AlAs into AlxOyis used to define lateral device dimensions of 2, 5, and 8 &mgr;m. Initial results demonstrate a continuous‐wave room‐temperature lasing threshold current of 97 &mgr;A for a 2 &mgr;m device and 220 &mgr;A for an 8 &mgr;m device. We show that lasing operation is influenced by the AlxOylocated only 200 A˚ from the quantum well. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113346

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Highly textured strontium barium niobate thin films were depositedinsituby low pressure metalorganic chemical vapor deposition. [001]‐oriented strontium barium niobate films on single crystal (100) magnesium oxide substrates were obtained at a growth temperature of 800 °C. Second‐harmonic generation of 1.064 &mgr;m incident light was measured on the thin films. The nonlinear optical susceptibility of the films was as high as 8.7 times that of quartz (∼3.0 pm/V), which is comparable to the bulk value. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113347

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Nanometer‐scale Si structures have been fabricated by anodic oxidation with an atomic force microscope (AFM) and dry etching using an electron cyclotron resonance (ECR) source. The AFM is used to anodically oxidize a thin surface layer on a H‐passivated (100) Si surface. This oxide is used as a mask for etching in a Cl2plasma generated by the ECR source. An etch selectivity ≳20 was obtained by adding 20% O2to the Cl2plasma. The AFM‐defined mask withstands a 70 nm deep etch, and linewidths∼10 nm have been obtained with a 30 nm etch depth. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113348

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The transformation of titanium silicide from the C49 to the C54 structure was studied using x‐ray diffraction of samples containing arrays of narrow lines of preformed C49 TiSi2. Using a synchrotron x‐ray source, diffraction patterns were collected at 1.5–2 °C intervals during sample heating at rates of 3 or 20 °C/s to temperatures of 1000–1100 °C. The results show a monotonic increase in the C54 transition temperature by as much as 180 °C with a decreasing linewidth from 1.0 to 0.1 &mgr;m. Also observed is a monotonic increase in (040) preferred orientation of the C54 phase with decreasing linewidth. The results demonstrate the power ofinsitux‐ray diffraction of narrow line arrays as a tool to study finite size effects in thin‐film reactions. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113349

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Full structural studies of condensed media under high pressure by neutron powder diffraction have been limited in practice to 2–3 GPa for several decades. This range is in general too small to allow a precise determination of the pressure dependence of atomic coordinates. As a consequence, almost no direct measurements exist, for example, of the pressure dependence of the bond lengths in H2and the planetary ices. In this letter, a technique is presented which makes it possible to pressurize samples of 35 mm3volume up to 30 GPa and to collect neutron diffraction patterns in a few hours by time‐of‐flight techniques. This method provides data which can be treated by Rietveld profile refinement methods, as demonstrated on a sample of D2O ice VII at 26 GPa. This represents a tenfold increase of the pressure range over which refinable neutron diffraction data can be obtained and should have a number of applications in such fields as fundamental physicochemistry, and geo‐ and planetary sciences. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113350

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

SiO2hole traps with small cross section (&sgr;≤10−15cm2) in Al gated metal–oxide–silicon capacitors have been studied using vacuum ultraviolet hole injection in combination with capacitance voltage measurements. The data show that small &sgr; hole traps are related to H/hole pairs or protons trapped in the oxide. Since accumulated positive charge and H vanish simultaneously from the oxide in times of the order of 102s, it is proposed that they migrate together through the oxide as a proton. The small &sgr; hole traps are not associated with defects in the as‐grown oxide; they are generated by radiation induced release of atomic H. Their number is governed by the rates of release and of removal (dimerization) of atomic H. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113351

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Amorphous silicon–carbon (a‐SiC) alloy films were deposited by using the hot‐filament chemical vapor deposition technique. The gas mixture containing different concentrations of silane in methane with additional dilution in hydrogen formed the source gas. Films were characterized for infrared and optical absorption and Raman scattering. The films deposited under ‘‘starving’’ hot‐filament conditions exhibited properties characteristic of stoichiometric carbon‐freea‐SiC material. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113352

出版商:AIP    

年代:1995

数据来源: AIP