摘要:

Total internal diffraction of plasmon surface polariton fields by a dielectric phase grating is described. The grating was fabricated by partly desorbing thin organic multilayers deposited on top of the plasmon‐carrying Ag‐air interface through the regularly spaced holes of an electron microscope grid. The diffraction pattern shows for various angles of incidence a characteristic intensity distribution which can be understood taking into account a grating wave vector mediated coupling of the two plasmons corresponding to the two different layer structures.

ISSN:0003-6951    

DOI:10.1063/1.98865

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The frequency response and the frequency‐mixing properties of the tunneling junction of a scanning tunneling microscope (STM) were investigated using the radiation of two CO2lasers. Difference frequencies of up to 90 MHz were detected over a wide range of bias voltages and tunneling currents. At tunneling currents typical of STM operation the beat signal decreases as the bias voltage is increased. However, this dependence is reversed at higher tunneling currents, where the STM begins to resemble a point‐contact metal‐insulator‐metal diode. For low tunneling currents the generation of the beat signal is attributed mainly to thermally assisted tunneling.

ISSN:0003-6951    

DOI:10.1063/1.98866

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Single‐mode rib waveguides with low propagation loss (0.2 dB/cm) were fabricated on GaAs/AlGaAs single heterostructures by dry etching. The attenuation of these guides was measured to study the effect of rib structure on propagation loss at 1.52 &mgr;m. An increase in loss with increased rib height and decreased rib width was associated with scattering due to a rib surface roughness of approximately 50 nm for ion milled waveguides. Fabrication with reactive ion etching reduced the rib roughness and its associated scattering loss by a factor of 3 or more in waveguides with strong optical confinement (effective index difference of 0.012) of the fundamental guided mode.

ISSN:0003-6951    

DOI:10.1063/1.98867

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A new first‐principle theory that includes the higher order field and carrier effects in semiconductor waveguide refractive index modulators has been developed. For the first time, the relative importance of the electrorefractive, band filling, linear electro‐optic, and plasma effects is shown. The theory agrees well with measurements from experimental AlGaAs/GaAs depletion‐edge‐translation (DET) phase modulators that have given record levels of phase shift per volt per unit length, and it suggests an improved DET device design with much larger phase shifting efficiency. The required drive voltage/bandwidth figure of merit,V&pgr;/ &Dgr;f, for this configuration (without including quantum wells) is lower than for any other existing optical index modulator.

ISSN:0003-6951    

DOI:10.1063/1.98868

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Periodical short pulse trains were observed in a long pulse, low current, low voltage waveguide mode free‐electron laser. The pulse width and the pulse train intervals of the periodical short pulse trains were about a few ns and about 23 ns, respectively. These pulse trains can be explained as self‐mode‐locked oscillations of a free‐electron laser.

ISSN:0003-6951    

DOI:10.1063/1.98869

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Hydrogenated amorphous boron films have been produced by a toroidal glow discharge of B2H6/He mixtures at low pressures (10−2Torr). Chemically stable pure films with a low hydrogen content can be formed at a moderate substrate temperature (∼200 °C) when the diborane flow rate is raised above 10 sccm with the discharge power lowered below 100 W. The controllability of H content is potentially interesting for applications in the coating of nuclear fusion devices, as well as for use in electronic devices.

ISSN:0003-6951    

DOI:10.1063/1.98870

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Residual dislocations in a P‐alloyed and an undoped GaAs crystal grown by the liquid encapsulated Czochralski method were investigated by transmission electron microscopy. In the undoped GaAs, dislocation bundles constructing cell walls and/or lineages consist of at least three different Burgers vectors. In the P‐alloyed GaAs with low dislocation density, individual dislocation reactions were observed. Sessile dislocations were found to be formed by an interaction between two kinds of dislocations. The sessile dislocation formation may be a first step for the complicated dislocation structure in the undoped crystal.

ISSN:0003-6951    

DOI:10.1063/1.99007

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

High‐quality amorphous silicon germanium (a‐SiGe:H) films are produced by a new ‘‘catalytic chemical vapor deposition (CTL CVD)’’ method. In the method, a SiH4, GeH4, and H2gas mixture is decomposed without using any plasmas or photochemical excitation, but using only the thermal or the catalytic reaction with a heated tungsten catalyzer. Photoconductive properties of CTL CVDa‐SiGe:H are apparently not degraded as the Ge content increases. The photoconductivity and the photosensitivity for AM‐1 of 100 mW/cm2are 10−5–10−4(&OHgr; cm)−1and 104, respectively, even for the sample of optical band gap of 1.40–1.45 eV.

ISSN:0003-6951    

DOI:10.1063/1.98871

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Very thin, high carrier concentration layers for high performance GaAs field‐effect transistors are realized by lamp annealing, combined with low‐energy (<30 keV) ion implantation. The characteristics of these thin layers are investigated by the Hall effect, capacitance‐voltage, photoluminescence, and secondary ion mass spectrometry (SIMS). The optimum temperature giving the maximum sheet carrier concentration is the result of a balance between damage recovery and acceptor generation. The optimum temperature decreases as the implantation energy is reduced. The effective implanted layer thicknesses obtained by SIMS are larger than the Lindhard–Scharff–Schiott calculated values. The minimum effective active layer thickness of 0.045 &mgr;m is obtained with a 10‐keV implanted sample. This value is about one‐half that obtained for the 30‐keV implanted furnace annealed sample.

ISSN:0003-6951    

DOI:10.1063/1.98872

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Lattice‐matched ZnSe0.95S0.05epitaxial layers have been grown on (100) oriented GaAs substrates by atmospheric pressure metalorganic vapor phase epitaxy. Blue room‐temperature photoluminescence is observed and the interface is both compositionally and structurally abrupt as shown by secondary ion mass spectrometry and high‐resolution transmission electron microscopy.

ISSN:0003-6951    

DOI:10.1063/1.98873

出版商:AIP    

年代:1987

数据来源: AIP