摘要:

The recombination lifetime in CdSxSe1−xsemiconductor‐doped glass was measured by time‐resolved photoluminescence. It was found that long‐term exposure of the glass to high‐intensity laser pulses produced a permanent reduction of the free‐carrier lifetime from 80 ps to less than 10 ps. This change could be reversed by thermal annealing and should have applications to ultrafast optical signal processing.

ISSN:0003-6951    

DOI:10.1063/1.100824

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Experiments on the ablation of undoped polytetrafluoroethylene (Teflon) with 300 fs UV excimer laser pulses at 248 nm are reported for the first time. In contrast to standard excimer laser pulses, these ultrashort pulses ablate Teflon with good edge quality and no signs of thermal damage for fluences down to 0.5 J/cm2with removal rates on the order of 1 &mgr;m per pulse.

ISSN:0003-6951    

DOI:10.1063/1.100831

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Increasing absorption of 10.6 &mgr;m laser radiation by Cu and Al surfaces pretreated with excimer laser pulses has been measured. The effective coupling is shown to approach 100% under certain irradiation conditions. This increased absorption arises from a combination of excimer roughening and oxidation.

ISSN:0003-6951    

DOI:10.1063/1.100839

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We demonstrate for the first time that large quantum‐confined Stark effect can be obtained in high quality InGaAsP/InP quantum wellp‐i‐nheterostructures. The compositional flexibility of this material system is particularly suited for quantum well device applications in optical communications systems operating between 1.55 and 1.3 &mgr;m. We measure the magnitude of the shift of the ground‐state exciton transition with applied electric field and find that it is significantly enhanced over ternary wells. We have also determined the electro‐optic intensity and phase modulation response in these structures.

ISSN:0003-6951    

DOI:10.1063/1.100821

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report the operation of a &bgr;‐BaB2O4singly resonant optical parametric oscillator broadly tunable in the ultraviolet, visible, and infrared regions of the spectrum. This optical parametric oscillator was pumped at 266 nm and was continously tunable throughout 0.33–1.37 &mgr;m. A novel cavity design was implemented which has applicability to other parametric oscillators. The oscillation threshold of this device was measured and compared to the calculated result.

ISSN:0003-6951    

DOI:10.1063/1.101434

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A lateral structure metal‐semiconductor‐metal photodiode has been fabricated on GaInAs, in which an AlInAs/GaInAs graded superlattice has been incorporated. This photodiode has exhibited a dark current lower than 100 nA, an internal quantum efficiency of greater than 80% at a wavelength of 1.3 &mgr;m, and a capacitance of 40 fF, all at the bias voltage of 10 V. The response speed of this photodiode has been characterized by electro‐optic sampling to exhibit a full width at half maximum of 14.7 ps.

ISSN:0003-6951    

DOI:10.1063/1.100822

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Electromigration experiments have been carried out on aluminum thin films which have been deposited on oxide‐free (111) silicon by employing the ‘‘ionized cluster beam’’ technique as well as other related deposition methods. It has been found that the same high electromigration resistance and film structure is obtained with or without utilizing a nozzled crucible and with or without applying ionization and acceleration voltages during deposition. The conclusions are supported by electromigration lifetime measurements, scanning electron micrographs, optical micrographs, reflective high‐energy electron diffraction, and x‐ray diffraction.

ISSN:0003-6951    

DOI:10.1063/1.100823

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Micron‐sized loops of high‐mobility two‐dimensional electron gas have been made on GaAs‐AlGaAs heterostructures using a novel split‐gate technique. Aharonov–Bohm oscillations of amplitude up to 20% of the device resistance have been observed at very low temperatures (T<100 mK), together withh/2eoscillations which appear to be due to interference between pairs of time‐reversed paths nearB=0. Theh/eperiod is found to vary by ∼25% with magnetic field, possibly as a result of the formation of edge states. In the quantum Hall effect, plateaus inRxxare seen at highBdue to variations in carrier concentration across the ring, which may cause backscattering of some edge states.

ISSN:0003-6951    

DOI:10.1063/1.100818

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

High quality GaAs films with dislocation densities of 1–2×106cm−2on (100)Si substrates have been obtained for combination of strained‐layer superlattice insertion and thermal cycle growth using the metalorganic chemical vapor deposition method. In this letter, remarkable reduction effects of dislocation density in the GaAs layers due to InGaAs/GaAs and InGaAs/GaAsP strained‐layer superlattice insertion on Si have been analyzed by calculating the dislocation force exerted by the misfit due to the strained‐layer superlattice insertions. Threshold layer thickness needed for dislocation reduction and critical thickness for dislocation generation have been clarified for several strained‐layer superlattice systems.

ISSN:0003-6951    

DOI:10.1063/1.100819

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report the realization of a high mobility [&mgr;&bartil;4.8×105cm2/(V s)] selectively doped GaAs/AlxGa1−xAs multiple quantum well structure with low density (ns&bartil;1.7×1011cm−2for each of the 85 wells) grown by molecular beam epitaxy. The activation energy for the fractional quantum Hall state at the Landau‐level filling factor &ngr;=1/3 is &Dgr;&bartil;2 K, the highest value ever reported for any multiple quantum well structure. Such a structure is nearly ideal for studies of the thermal properties of the two‐dimensional electron system in the fractional quantum Hall regime.

ISSN:0003-6951    

DOI:10.1063/1.100820

出版商:AIP    

年代:1989

数据来源: AIP