摘要:

A novel AlGaAs/GaAs distributed Bragg reflector laser utilizing a multiquantum well structure both as an active waveguide and as a low loss passive waveguide was fabricated. The threshold current was 102 mA at room temperature, and the differential quantum efficiency for the edge‐ and surface‐emitted light was 16% and 3.7%, respectively. No mode hopping was observed in a temperature range of 35 K. A 0.17°×17° far‐field pattern was obtained for the surface‐emitted light.

ISSN:0003-6951    

DOI:10.1063/1.97668

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Continuous and pulsed phase‐locked operation of a high power GaInAsP‐InP semiconductor laser emitting at 1.3 &mgr;m has been achieved. The laser consists of a seven‐striped array of ridge‐island lasers fabricated by a two‐step low‐pressure metalorganic chemical vapor deposition growth technique. Linear output powers greater than 300 mW (pulsed) and 120 mW (cw) have been obtained with no facet coatings. The far‐field full widths at half power, both parallel and perpendicular to the junction plane, were 3° and 45°, respectively, at 10 mW (at 20 °C) which is evidence for strong stripe‐to‐stripe coupling.

ISSN:0003-6951    

DOI:10.1063/1.97669

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

High power, buried heterostructure laser with flared waveguide horns have been grown by a two‐step metalorganic chemical vapor deposition process. Powers up to 120 mW cw in a single longitudinal and transverse mode have been obtained from a single stripe laser. The flared waveguides decrease the lateral far‐field divergence from 25° to 11° while supporting only the lowest order transverse mode.

ISSN:0003-6951    

DOI:10.1063/1.98237

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A new, low bias tilt field‐effect liquid crystal display (LCD) is presented with better image quality than supertwist or superbirefringence LCD’s at the same high level of multiplexing. In its positive contrast mode, the display image is black on white with virtually no inherent coloration and with a comparably large contrast as that of twisted nematic LCD’s. The viewing range of the display is as wide as that of superbirefringence LCD’s, whereas its image quality is an order of magnitude less dependent on cell gap variations. With specifically designed liquid crystal mixtures, multiplexing ratios of 1000:1 and response times below 300 ms result.

ISSN:0003-6951    

DOI:10.1063/1.98238

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Transverse oscillations of a relativistic electron beam propagating in a beam‐induced ion channel have been theoretically investigated and experimentally observed. Good agreement between experimental observations and theoretical calculations strongly suggests that these oscillations may be caused by the ion hose (ion resonance) instability.

ISSN:0003-6951    

DOI:10.1063/1.98239

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The density of radiation‐induced traps at the Si/SiO2interface in TiSixand WSixgate metal‐oxide‐semiconductor capacitors is shown to depend on the stoichiometry (xvalue) of the silicide. The dependence is such that capacitors with metal‐rich silicide gates exhibit a smaller increase in interface traps than do capacitors with silicon‐rich gates. These results can be qualitatively explained by the dependence of the silicide stress on stoichiometry—metal‐rich films are under large tensile stress that inhibits the generation of radiation‐induced interface traps.

ISSN:0003-6951    

DOI:10.1063/1.98240

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We report on the use of a cw Nd:yttrium aluminum garnet infrared laser to probe by Raman scattering the damaged layers of GaAs implanted with high‐energy(∼2 MeV) protons and deuterons. Such layers are too deep into the material to be probed by visible light. As the implanted area is approached laterally, we observe a gradual decrease in the scattering intensity of the longitudinal optical and transverse optical phonons and a downward shift of their frequencies. These effects are attributed to defect‐induced absorption and lattice strains. The results demonstrate the advantages of the technique for studying the damage in deeply buried layers of radiation‐modified materials.

ISSN:0003-6951    

DOI:10.1063/1.98241

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Photocurrent‐voltage measurements at different wavelengths exhibit the valence‐band discontinuity of a hydrogenated amorphous silicon/hydrogenated amorphous silicon carbide heterojunction. A band discontinuity of ∼100 meV is deduced based on a tunneling model for a hole barrier. This energy gap is relatively small compared to that for the conduction band, but significantly affects the characteristics of heterojunctionp‐i‐nsolar cells.

ISSN:0003-6951    

DOI:10.1063/1.98242

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Model contacts to GaAs that include nonalloyed layered structures of Au, Ge, and Ni in various combinations are used to establish a correlation between interface composition and large changes in barrier height &fgr;B. The interface Fermi levelEiFand chemistry during initial contact formation were investigated by x‐ray photoemission spectroscopy; the corresponding &fgr;Bfor the thick contact was obtained by current‐voltage (I‐V) measurement. The circumstances under which a thin (∼10 A˚) Ge layer at the GaAs interface can produce &fgr;B=∼0.25–0.4 eV (as measured byI‐V) are described. For all model contacts examined a &fgr;Brange from ∼0.25 to 0.9 eV is observed. This result questions the usual assumption of a relatively fixed &fgr;Bof ∼0.8 eV for the alloyed AuGeNi contact and offers an alternative explanation for the mechanism of ohmic contact formation. The conditions that define the exceptionally low &fgr;Bcontacts provide a guide for the design of nonalloyed tunnel ohmic contacts.

ISSN:0003-6951    

DOI:10.1063/1.98215

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Silicon surfaces were exposed to reactive ion etching with CCl2F2, followed by low pressure chemical vapor deposition of silicon nitride. Examination with transmission electron microscopy shows a 5‐nm homogeneous layer with interfacial roughness about the order of the layer thickness between the nitride and the silicon substrate. Analysis with spatially resolved electron energy loss scattering indicates that this phase is Si2N2O. The causes for the formation of this layer and its implication on very large scale integration technology are discussed.

ISSN:0003-6951    

DOI:10.1063/1.98216

出版商:AIP    

年代:1987

数据来源: AIP