摘要:

The 5‐K photoluminescence (PL) spectra of undoped semi‐insulating GaAs are observed as a function of carbon implantation dose (after 850°C annealing using a SiO2cap). Results show that although the intensity of the bound exciton line at 1.514 eV remains fairly independent of carbon concentration up to 1017cm−3carbon, the intensity of the conduction band to acceptor peak at ∼1.494 eV increases monotonically with carbon implant dose. This is the first direct confirmation that the 1.494‐eV transition is due to carbon. The observed correlation between implanted carbon doses and PL intensities at high excitation levels is the basis of an analytic technique for C assessment in GaAs.

ISSN:0003-6951    

DOI:10.1063/1.92830

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Analytic and experimental results are presented to demonstrate the advantages of using a cw preheat spot in conjunction with a larger write spot in an optical disc recording system. When compared with conventional single spot writing, the use of preheat allows smaller holes to be recorded while requiring up to 50% less power from the write source. Results are presented for a preheat‐to‐write‐spot ratio that assumes a He‐Cd laser preheat source and semiconductor laser write source. An increase in packing density of almost a factor of 2 and an increase in bandwidth of 15% are demonstrated.

ISSN:0003-6951    

DOI:10.1063/1.92831

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Nuclear lasing of Ar 10% Xe at 760 Torr with a thermal neutron flux of 3.5×1016n/cm2 s has produced an output power of 50 W. Lasing occurred at 2.6 &mgr;m in Xe‐I. The argon buffer gas is shown to efficiently stop fission fragments at reasonable pressures emitted from235U3O8coatings. A unique folded optical path was used to increase the excited gas volume which in turn increases laser output.

ISSN:0003-6951    

DOI:10.1063/1.92832

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Laser emission from a 1.5‐&mgr;m wavelength InGaAsP/InP diode was shown to be efficiently converted to visible or to near‐infrared light by Er‐containing infrared‐excitable phosphors. The visible emission has been markedly enhanced in Yb‐sensitized phosphors under 0.97‐&mgr;m wavelength auxiliary light irradiation especially under weak 1.5‐&mgr;m wavelength excitation. The enhancement mechanism has proved to be Yb‐sensitized quantum counter action.

ISSN:0003-6951    

DOI:10.1063/1.92833

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The transmission coefficient for sound at an interface between a fluid and a porous medium has been derived. Numerical values are compared with experimental values obtained by Plona [Appl. Phys. Lett. 36, 259 (1980)] who transmitted a short ultrasonic pulse through a porous disk. The good agreement between theory and experiment supports the conclusion that a second compressional wave has been observed.

ISSN:0003-6951    

DOI:10.1063/1.92834

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Energy flow to a target rear surface due to hot electrons was experimentally studied by irradiating a 10‐&mgr;m wavelength laser. Lateral heat conduction produced a plasma of low and uniform temperature, whose size was nearly one order larger than that of a laser focal spot for plane targets. Experimental results were simulated by using a one‐dimensional hydrodynamic simulation code to investigate the effects of hot electron diffusion.

ISSN:0003-6951    

DOI:10.1063/1.92835

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Measurements of the Young’s modulus are reported forin‐situformed Cu‐Nb wire composites containing 7.5 and 15.0 vol.% niobium filaments. Comparison of the experimental values for the as‐drawn and annealed wires shows rapidly diverging trends with decreasing wire diameter. In composites with the smallest filaments (50–200 A˚) the modulus increases by almost 100% upon annealing and exceeds the maximum values calculated from bulk elastic constants. However, plastic strain (in elongation) of as little as 0.02% results in a substantial (∼25%) reduction in modulus, suggesting that most of the enhancment in the annealed composites originates from the thermally induced elastic strains at the matrix‐filament interfaces.

ISSN:0003-6951    

DOI:10.1063/1.92842

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The complete solid‐phase epitaxial regrowth of ion‐implanted layers in GaAs was obtained during a short (10 min) capless furnace anneal at a temperature of 475 °C. Two factors believed responsible for the incomplete regrowth of layers have been identified. First, the damage density from the implant should not exceed a critical value determined by a Boltzmann calculation. Second, the growth of polycrystalline material from the surface observed by transmission electron microscopy is a competitive mechanism. As+implants, whose doses and energies were selected to achieve the correct damage density, and to ensure that its value was maintained in the near‐surface region, led to a complete recrystallization.

ISSN:0003-6951    

DOI:10.1063/1.92816

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Secondary ion mass spectrometry was used to profile deuterium concentrations [D] in 100‐200‐nm‐thick SiO2films, which were grown by thermal oxidation of silicon in D2O steam pressures of 0.05‐8 atm and at temperatures of 550‐1000 °C. Deuterium was used to simulate hydrogen chemistry in steam oxidations and is readily detected in the presence of high background concentrations of hydrogen in the sputtering ambient. Structure observed here in D profiles, and previously in H profiles, near the SiO2‐Si interface are due predominantly to abrupt changes in ion yields as the surface charging conditions change. The 1‐atm profiles generally exhibit an increase in [D] in the SiO2toward the Si interface; the average [D] is nearly constant at 0.6‐1.0×1020cm−3for oxidations at 800‐1000 °C and rises to 6×1020cm−3at 600 °C. It is argued that the D is predominantly in the form of Si‐OD. At 800 °C and 0.05‐8 atm, the average OD concentration in the oxide film is approximately proportional to (steam pressure)1/2. This is the first demonstration of the simple equilibrium reaction between ambient water and the as‐grown oxide layer.

ISSN:0003-6951    

DOI:10.1063/1.92817

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The rapid annealing of ion implantation damage in silicon using the radiation from a graphite heater has been demonstrated. Complete 3‐in.‐diam wafers were annealed in a single 10‐sec exposure with high activation for implants of boron (50 keV; 1×1015cm−2) and moderate activation for high‐dose arsenic implants (140 keV; 6×1015cm−2). Dopant redistribution was ∼1000 A˚ for boron and ∼200 A˚ for arsenic. Leakage currents of implantedp+nandn+pdiodes were comparable to those of furnace‐annealed control wafers and indicate good crystallinity in the depletion region near the junction. Diode leakage uniformity across the wafers was also excellent.C‐Vmeasurements on oxides annealed by this technique showed flatband voltages within 0.5 V of those measured on control wafers. This method of annealing implant damage is a practical alternative to those involving more elaborate power sources such as lasers, electron beams, or high‐intensity arc lamps.

ISSN:0003-6951    

DOI:10.1063/1.92818

出版商:AIP    

年代:1981

数据来源: AIP