摘要:

The refractive indexn, extinction coefficientk, and optical band gapEoptof nitrogen incorporated amorphous carbon films &agr;‐C:N have been investigated by spectroscopic ellipsometry. The effect of the incorporated nitrogen on the bonding configuration of carbon atoms has been discussed in term of the optical behavior of the films. The results show that nitrogen incorporation into the films stabilizes the tetrahedral bonds of carbon atoms, resulting in lower values of bothnandk. However, if the nitrogen incorporation is accomplished by means of excessive N+ion bombardment, the formed &agr;‐C:N films possess zero gap and are more ‘‘graphitelike.’’ ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115960

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report spatially nondegenerate four‐wave mixing in a broad‐area laser diode that acts as a fast phase conjugate mirror with nanosecond response times and high efficiencies. Phase conjugate reflectivities were found to depend strongly on the bias current of the broad‐area laser diode. Operating the laser diode in an injection‐locked regime above the lasing threshold gave phase conjugate reflectivities as high as 165%. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115961

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We have investigated three different quasi‐phase‐matching approaches to second‐harmonic generation (SHG) in DANS (4‐dimethylamino‐4′‐nitrostilbene) poled polymer channel waveguides at 1.5 &mgr;m. Periodic photobleaching and periodically poled electrodes deposited directly on the film produced unacceptably high propagation losses. However, periodic electrodes on the substrate gave low losses and useful SHG. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115962

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The construction of a high power single quantum well buried heterostructure InGaAsP/InP (&lgr;=1.3 &mgr;m) and InGaAsP/GaAs (&lgr;=0.8 &mgr;m) laser diode with reduced values of parasitic capacitance has been proposed and investigated. This design uses a 3.5 &mgr;m thick polyimide layer in the current confinement regions of the buried laser. The active area of the laser is surrounded by semiconductor material and the entire structure was grown by liquid phase epitaxy. Lasers with &lgr;=1.3 &mgr;m and resonator lengths of 310, 450, and 560 &mgr;m exhibited modulation bandwidths of 8.7, 9.2, and 6.6 GHz at operating powers of 41, 72, and 91 mW, respectively. Lasers with &lgr;=0.8 &mgr;m and a 600 &mgr;m resonator showed a 5.6 GHz modulation bandwidth at an output power of 98 mW. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115963

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Stable blue photoluminescence (PL) at 580 nm visible to the naked eye has been observed for the samples consisting of Ge nanocrystals (nc‐Ge) embedded in a silicon oxide (SiO2) solid matrix, fabricated by atmospheric pressure chemical vapor deposition techniques. Raman spectroscopy measurement strongly suggests the existence of Ge nanocrystal in the SiO2matrices. The size of nc‐Ge is dependent on aftergrowth thermal treatment under nitrogen ambient, and it is found that temperature above 700 °C for 1 h only exhibits the PL peak at the visible wavelength. The samples annealed for longer times at 700 °C do not exhibit any PL peak which is correlated with the change of the nanocrystal size. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115964

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Thin film organic electroluminescent devices are described which employ a blue‐emitting species as a layer sandwiched between the hole transporter bis(triphenyl)diamine and the light emitting electron transporter tris(8‐hydroxyquinoline)aluminum to obtain bright (≳4700 cd/ m2) efficient (0.5 lm/W) white emission. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115965

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The energy of Cr4+local modes and the energy and dynamics of Mg2SiO4phonon modes involved in the nonradiative relaxation of photoexcited impurity Cr4+ions in forsterite crystal were measured. The experimental results suggest that resonance in energy between local vibrations of the impurity ion and lattice (phonon) modes of the host crystal plays a crucial role in selecting the phonons which participate in the nonradiative relaxation of the photoexcited ions in crystals. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115966

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Electromigration in thin films of aluminium and aluminium alloys is shown to lead to stepwise increases of the electrical 1/fnoise. These are attributed to the generation of highly mobile defect configurations by a nucleation‐and‐growth process. It is conjectured that among them may be the defects that are responsible for the eventual failure of VLSI electronic devices by electromigration damage. 1/fnoise promises to be an early indicator of this damage. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115967

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Oxygen and nitrogen impurities increase the dark conductivity of hydrogenated amorphous silicon (a‐Si:H), due to their donorlike behavior. An appropriate amount of boron doping recovers these values to the original ones unless the effect of band gap widening appears. The midgap absorption spectra of the compensateda‐Si:H are identical to those of intrinsica‐Si:H both at initial and light‐soaked states. The major effect of the oxygen and nitrogen is the creation of donors, which show a similar behavior to those by phosphorus—only a small fraction of the oxygen and nitrogen produces donors, the rest is included in thea‐Si:H network without causing any other significant effect until alloying effects appear. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115968

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Epitaxial growth of 6H–SiC on 6H–SiC(0001) via two‐dimensional nucleation was realized at 930 °C by solid‐source molecular beam epitaxy using the alternate supply of Si and C. The deposition was controlled to an atomic level by surface superstructures. The growth was started on the (&sqrt;3×&sqrt;3)R30° surface which turns into the (1×1) phase upon deposition of about 1 monolayer silicon and recurs after subsequent deposition of about 1 monolayer carbon. Deviations from the monolayer deposition and, moreover, growth around substrate related defects result in the deposition of 3C–SiC. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115969

出版商:AIP    

年代:1996

数据来源: AIP