摘要:

Coupling‐loss‐arrested misaligned semiconductor laser arrays are designed and fabricated by liquid‐phase epitaxy. In these devices, the losses in the normal misaligned arrays is collected by a gain‐induced positive waveguide, and then the collected light couples with light in the adjacent waveguides evanescently, therefore avoiding the coupling loss and strengthening the coupling. The constructed co‐cavity element should have better characteristics with respect to transverse‐mode selection. A clean single‐lobe far field as narrow as 3° and a relatively low threshold of 130 mA for a seven‐element array are obtained.

ISSN:0021-8979    

DOI:10.1063/1.346294

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The recent findings of Scheer, Wilhelm, and Lewerenz[J. Appl. Phys.66, 5412 (1989)] regarding the application of the electron‐beam‐induced current technique in both the vertical and planar configurations to determine the minority‐carrier diffusion length in low‐diffusion‐length material are compared to the results of an earlier analysis [J. Appl. Phys.57, 1978 (1985)] of the same subject. The differences are briefly discussed.

ISSN:0021-8979    

DOI:10.1063/1.346295

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The application of the vertical electron‐beam‐induced current configuration for diffusion lengths in the submicron meter range is briefly discussed. Results of our experiments [J. Appl. Phys.66, 5412 (1989)] are compared to earlier investigations by other authors.

ISSN:0021-8979    

DOI:10.1063/1.346296

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Based on Davis’ model for the lateral restoring force on a magnet levitated above a superconductor [J. Appl. Phys.67, 2631 (1990)], we calculate the restoring force as a function of lateral displacement for a more realistic magnetic field profile.

ISSN:0021-8979    

DOI:10.1063/1.346297

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

P/Be and Ar/Be dual implantations were performed into In0.53Ga0.47As. Significantly higher Be dopant activation was obtained for P/Be dual implantation compared to Be implantation. Lower dopant activation was obtained for Ar/Be dual implantation. Be in‐diffusion during annealing is reduced for both P/Be and Ar/Be dual implantations.

ISSN:0021-8979    

DOI:10.1063/1.346298

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have analyzed the incorporation of Si &dgr; doping during the molecular‐beam epitaxial (MBE) growth of GaAs and Al0.25Ga0.75As using secondary‐ion mass spectroscopy. At high substrate temperatures (≥580 °C) a significant and asymmetric broadening is observed in both GaAs and Al0.25Ga0.75As. This is due to the combined effect of thermal diffusion and migration towards the surface during MBE growth. This study points out that a low substrate temperature (≤540 °C) and a short time are required during MBE crystal growth to achieve confined &dgr; doping.

ISSN:0021-8979    

DOI:10.1063/1.346299

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Measured length variations of laser written marks in rare earth–transition metal (RE‐TM) optical data storage media were found to be a strong function of test conditions. In particular, the mark length standard deviation was found to be inversely proportional to the difference between the threshold and bias power levels. Differences in mark length variabilities of various RE‐TM compositions written with the same bias power were found to be attributable to their differing marking thresholds.

ISSN:0021-8979    

DOI:10.1063/1.346300

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Thin superconducting films of YBa2Cu3O7−xwere deposited onto (100) SrTiO3substrates at 750 °C in 100 and 200 mTorr of O2, by ArF excimer laser ablation. The as‐deposited films were strongly oriented with thecaxis perpendicular to the surface when they were cooled to room temperature in oxygen. The highest values of transport critical current density (Jc≳105A/cm2below 80 K) were observed in films cooled in flowing O2. We find that, in all films,Jcfollows a power law (1−T/Tc)nwithn≊2, near the critical temperature,Tc, whenTcis defined as the temperature at whichJc=0. It appears that this behavior is governed by the short coherence lengths in this high‐Tcmaterial, as suggested by G. Deutscher and K. A. Mu¨ller [Phys. Rev. Lett.59, 1745 (1987)], and not by the specific nature of the large‐scale structure of the films.

ISSN:0021-8979    

DOI:10.1063/1.346301

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A technique for the determination of the critical current of superconducting thin films by a current‐dependent ac susceptibility measurement has been developed. This method has been used to characterize superconducting YBa2Cu3O7−xfilms growninsituat 1073 K by metalorganic chemical vapor deposition. Two superconducting phases with transition temperatures of 91 and 84 K have been detected by the measurement of ac susceptibility as a function of temperature even though the variation of resistance with temperature indicated a sharp transition. The critical current densities of the two superconducting phases have been determined from the variations of ac susceptibility with current at constant temperature and found to be equal to 1.14×104A/cm2and 3.6×103A/cm2at 75 K. The advantages of the technique in comparison to current methods of measurement of critical current are discussed.

ISSN:0021-8979    

DOI:10.1063/1.346302

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Thin films of high‐temperature superconducting YBaCuO deposited by dc‐sputtering on SrTiO3substrates are structured by electron beam lithography on a submicron scale. Details of the technology processes involved are presented. The sudden transition of structures below 1 &mgr;m into the semiconducting state is discussed.

ISSN:0021-8979    

DOI:10.1063/1.346303

出版商:AIP    

年代:1990

数据来源: AIP