摘要:

Grating‐surface emission from phase‐locked monolithic pairs of grating‐surface‐emitting diode lasers has been observed for the first time. Near‐diffraction‐limited far fields of 0.06°, spectra and power versus current plots of the coherent emission from the three second‐order distributed Bragg reflectors which form the laser cavity for two collinear gain sections are presented. The results suggest that linear arrays of grating‐surface emitters can be formed by connecting additional gain‐grating sections in series.

ISSN:0003-6951    

DOI:10.1063/1.98112

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The interaction between the plasma and the converter in a surface conversion negative ion source is studied. The converter consists of a porous tungsten button, through which liquid cesium diffuses towards the surface. This scheme results in a low cesium density in the discharge. Xe+and Ar+ions are used to simulate the sputtering effect of Cs+ion bombardment of the converter. The extracted H−beam energy profile and the conversion efficiency appeared to depend strongly on the heavy ion flux to the converter surface. The total H−current increases with an order of magnitude with increasing heavy ion flux. A maximum current density of 8 mA/cm2of H−ions has been extracted.

ISSN:0003-6951    

DOI:10.1063/1.98113

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have found that arsenic implanted into SiO2segregates at high temperatures into As‐rich spherical inclusions of 50–500 A˚ in diameter, provided that there is no free oxygen in the SiO2and the initial As concentration exceeds 1 at. %. The phase separation suppresses the diffusion of arsenic, even at temperatures as high as 1400 °C. We have discovered, however, that the As‐rich inclusions can be easily moved in a temperature gradient. They migrate towards the heat source at a rate of 2300 A˚/h in a gradient of 0.14 °C/&mgr;m, at 1405 °C, permitting their efficient removal from the oxide and into silicon.

ISSN:0003-6951    

DOI:10.1063/1.98114

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Single‐beam overwrite in an optical disk is reported using In‐Se‐Tl amorphous‐crystalline phase‐change recording films having very short erasing (crystallization) time of 0.2 &mgr;s. The lifetime of the amorphous state in an In‐Se‐Tl film is estimated to be longer than 10 years at 60 °C. This is due to its high crystallization temperature (135 °C) and high activation energy (2.6 eV). The phase‐change cycles can continue over 106cycles in stationary state experiments using test samples. The possibility of single beam overwrite (rewriting without prior erasing as with a magnetic disk) is verified by using a 1.6‐&mgr;m‐diam round laser beam spot irradiated on a 5‐in.‐diam disk rotating at 2400 rpm.

ISSN:0003-6951    

DOI:10.1063/1.98060

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Electrical properties of LaB6/GaAs(001) Schottky diodes have been studied by current‐voltage measurements. The diodes were made by depositing LaB6on chemically etched GaAs and molecular beam epitaxy prepared GaAs‐c(4×4) surfaces by electron beam evaporation. The barrier height and ideality factor show appropriate values for metal‐semiconductor field‐effect‐semiconductor application and do not change much by high‐temperature annealing. These results provide firm evidence that LaB6is a very promising candidate for self‐aligned gate material of GaAs integrated circuits.

ISSN:0003-6951    

DOI:10.1063/1.98061

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The band‐gap energy (Eg) of metalorganic vapor phase epitaxially (MOVPE) grown Ga0.5In0.5P lattice matched to (001) GaAs is presented as a function of a wide range of V/III ratios and growth temperatures. Photoluminescence, Raman scattering spectroscopy, transmission electron microscopy, and impurity diffusion were used to investigate this functional relationship. Two pieces of evidence are shown which demonstrate that MOVPE Ga0.5In0.5P epitaxial layers with ‘‘abnormal’’Eg∼1.85 eV and ‘‘normal’’Eg∼1.9 eV correspond to an ordered and a random (Ga,In) distribution on column III sublattices, respectively. In an ordered state, a sequence of (110) planes...GaGaInInGaGaInIn...in the [110] direction is the most probable distribution.

ISSN:0003-6951    

DOI:10.1063/1.98062

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Studies on the homoepitaxial growth of unintentionally doped GaAs by atmospheric pressure organometallic chemical vapor deposition using triethylarsenic and trimethylgallium have been carried out, and the effects of growth temperature, V/III ratio, and flow rate on film characteristics are reported. Mirrorlike epitaxial layers ofn‐type GaAs were obtained at substrate temperatures of 540–650 °C and at V/III ratios of 6.7–11. The carrier concentrations for these films were approximately 1016–1017cm−3, and from secondary ion mass spectroscopic analysis, the predominant epilayer impurities were determined to be both carbon and silicon.

ISSN:0003-6951    

DOI:10.1063/1.98063

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

High Schottky barrier height of &fgr;b=0.77 eV for Al/n‐Si was obtained by the nozzle jet beam deposition method in a conventional vacuum condition without post‐annealing. Previously, this high barrier height was only observable in the vacuum cleaved or sputter‐etched samples in an ultrahigh vacuum condition. The Schottky barrier height was reduced if a partially ionized jet beam with 0.1% ions was used in the deposition process and if a bias of ≥0.5 kV was applied to the substrate. The reduction of the Schottky barrier height is attributed to the surface damage caused by the energetic ion bombardment. It is shown that a high barrier height (&bartil;0.8 eV) and a low leakage current were retained after a relatively low‐temperature (&bartil;450 °C) annealing process if the applied bias was ≤1 kV.

ISSN:0003-6951    

DOI:10.1063/1.98064

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have used resonant Raman scattering by two longitudinal optical (LO) phonons in GaAs to probe ion implantation induced damage and its annealing. It was found that the strength of the two‐LO phonon peak is very sensitive to ion bombardment induced damage as demonstrated by the change in the Raman spectrum after sputtering with low‐energy Ar ions. For the study of ion implanted and thermally annealed material the two‐LO phonon scattering is more sensitive to the lattice perfection than the first‐order Raman spectrum especially in the region where electrical activation of the dopant sets in. Spatially resolved Raman spectroscopy revealed considerable variations of the crystalline perfection across the annealed sample. The latter study was particularly facilitated by using optical multichannel detection.

ISSN:0003-6951    

DOI:10.1063/1.98065

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have observed Stark shifts of quantum well intersubband transitions in a perpendicular electric field. Two samples consisting of 100 and 120 A˚ GaAs quantum wells separated by 350 A˚ AlGaAs barriers showed optical absorption peaks at 11.1 and 13.9 &mgr;m, respectively. In an electric field of 36 kV/cm, the 13.9 &mgr;m peak shifted to 13.7 &mgr;m and the 11.1 &mgr;m shifted to 11.0 &mgr;m, in good agreement with theoretical calculations. These tunable transitions can be applied to high‐speed infrared light modulators.

ISSN:0003-6951    

DOI:10.1063/1.98066

出版商:AIP    

年代:1987

数据来源: AIP