摘要:

The fast pulse response and the dc noise spectra of multiple quantum well lasers grown by metalorganic chemical vapor deposition and with different stripe widths are reported. A best rise time of 100 ps corresponding to a modulation bandwidth of ∼3.6 GHz, was obtained. The dc noise spectra showed a damped shot noise resonance at a high frequency (∼3.0 GHz). The improvement in pulse and noise performances of these lasers compared to conventional double heterostructure lasers is explained with the small active volume and the high charge densities present in quantum well lasers.

ISSN:0003-6951    

DOI:10.1063/1.93753

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The problem of sending an optical image through a phase‐distorting medium is discussed. It is shown that a simple lens is sufficient for transmitting the intensity of an image through a thin distorter. A phase conjugator and a lens can transmit the amplitude of an image through a thin distorter. Neither can transmit an undistorted image through a thick distorter. These results are experimentally verified using a self‐pumped phase conjugator.

ISSN:0003-6951    

DOI:10.1063/1.93754

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We describe the generation and detection of short acoustic pulses (∼10‐ns widths) in opaque plates, using weak laser pulses (less than 1‐mJ energy) for excitation. The longitudinal, shear, and surface acoustic waves generated by a single laser pulse can be time resolved by using a thin‐film piezoelectric transducer, and acoustic mode conversions at surfaces are clearly observable. This new photoacoustic material testing technique is useful for fast ultrasonic measurements or for detecting deep subsurface flaws.

ISSN:0003-6951    

DOI:10.1063/1.93755

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Low‐energy ion bombardment of hydrogenated amorphous silicon thin films during growth is shown to have a pronounced effect on growth morphology. The films studied have been prepared by reactive ion beam sputtering. For substrate temperatures ≳200 °C and hydrogen content in the films ≳20 at. %, a growth instability develops, which results in a rough film morphology. Ion bombardment during growth stabilizes the film growth, and results in smooth morphologies.

ISSN:0003-6951    

DOI:10.1063/1.93756

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Metal features with 10‐nm linewidths were produced on thick GaAs substrates using electron beam lithography. A single layer of polymethylmethacrylate (PMMA) was exposed by an approximately 2‐nm‐diam electron beam with energies ranging from 20 to 120 keV. Gold‐palladium lines less than 20 nm wide, and 15 nm thick, with center‐to‐center spacings of 70 nm, were produced over 15‐&mgr;m square fields at all electron beam energies by lift off. The exposure latitude increased significantly for higher electron energies, with 10‐nm‐wide metal lines formed using a 120‐keV writing beam.

ISSN:0003-6951    

DOI:10.1063/1.93757

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Recoil implantation of atoms from a layer deposited on a substrate is described in terms both of the linear cascade theory and of the continuous slowing down approximation. The model is valid within the limit of low incident ion doses and for layer thicknesses large enough to contain the main part of the deposited energy. Results are compared to experimental data with satisfactory agreement.Adhocexperiments can give information concerning the interactions of atoms colliding at low energy.

ISSN:0003-6951    

DOI:10.1063/1.93759

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Cerium‐activated phosphors are characterized by their fast luminescence decay. Gadolinium orthosilicate (Gd2SiO5) is a material possessing a high atomic number, and can also play host to the cerium activator. Cerium‐doped Gd2SiO5single crystals were grown by the Czochralski technique, and their luminescence properties were examined. The light output was 1.3 times larger than that of the best Bi4Ge3O12, and the decay constant was 60 ns at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.93760

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We formulate a rule which establishes a sufficient condition that an amorphous binary alloy will be formed by ion mixing of multilayered samples when the two constituent metals are of different crystalline structure, regardless of their atomic sizes and electronegativities. The rule is supported by the experimental results we have obtained on six selected binary metal systems, as well as by the previous data reported in the literature. The amorphization mechanism is discussed in terms of the competition between two different structures resulting in frustration of the crystallization process.

ISSN:0003-6951    

DOI:10.1063/1.93767

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Symmetric vortex‐antivortex and asymmetric vortex‐vortex modes have been observed in long Josephson tunnel junctions. These two modes manifest themselves as two nearly identical resistive branches in the current‐voltage characteristics. The voltage spacing between the symmetric vortex‐antivortex and the asymmetric vortex‐vortex modes is only about 3% of the voltage spacing between the first and second resistive branches. Except for a slight displacement in current these two modes almost completelyoverlapin voltage and current.

ISSN:0003-6951    

DOI:10.1063/1.93768

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Photoemission spectroscopy experiments with a synchrotron radiation source demonstrate that Hg depletion occurs near the surface during Al deposition on Hg0.72Cd0.28Te. The measured interface position of the Fermi level suggests that this depletion influences the effective Schottky barrier height.

ISSN:0003-6951    

DOI:10.1063/1.93769

出版商:AIP    

年代:1983

数据来源: AIP