摘要:

Real time ‘‘exclusive or’’ operation with an interferometer using a self‐pumped phase conjugate mirror is reported. Also, results of image subtraction and intensity inversion are shown.

ISSN:0003-6951    

DOI:10.1063/1.96795

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We demonstrate the first semiconductor‐optical fiber ring laser. The laser uses an InGaAsP traveling wave optical amplifier as the gain medium and a 1‐m length of highly birefringent fiber as the feedback loop. Output coupling is provided by a fiber directional coupler. The highly birefringent fiber is used as an intracavity wavelength filter, enabling single‐frequency oscillation with a narrow linewidth at a wavelength near 1.55 &mgr;m.

ISSN:0003-6951    

DOI:10.1063/1.97023

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Room‐temperature cw operation for InGaP/InGaAlP double heterostructure (DH) laser diodes on GaAs substrates was achieved for the first time. The DH wafers were grown by low‐pressure metalorganic chemical vapor deposition using methyl metalorganics. A lasing wavelength of 679 nm and a threshold current of 109 mA at 24 °C were obtained for an inner stripe structure laser diode with a 250‐&mgr;m‐long and 7‐&mgr;m stripe geometry. The laser operated at up to 51 °C. The characteristic temperatureT0was 87 K at around room temperature. The lowest threshold current density, 5.0 kA/cm2, was obtained with a 20‐&mgr;m stripe width laser diode under room‐temperature pulsed operation.

ISSN:0003-6951    

DOI:10.1063/1.96796

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Surface transformations in crystalline silicon are investigated, using 400 fs laser pulses, at intensities just above the melting threshold. Anomalous changes of surface heights are observed, and they are enhanced for shorter pulses. These experimental results are well understood with a picture that shock stress generated by the ultrashort pulse excitation causes anomalous surface transformations of crystalline silicon.

ISSN:0003-6951    

DOI:10.1063/1.96797

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Polymethylmethacrylate samples are irradiated with pulses from an ArF excimer laser at &lgr;=193 nm. The velocities of ablated particles are measured with the use of a quadrupole mass spectrometer. For laser fluences <120 mJ/cm2we observe thermal, Maxwell–Boltzmann velocity distributions. The photofragments possess a common temperature which increases with fluence to values as high as 3000 K.

ISSN:0003-6951    

DOI:10.1063/1.96798

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Further improvements in crystalline silicon solar cell performance have been obtained by combining the high levels of surface recombination control demonstrated in earlier passivated emitter solar cells with an improved optical approach. This approach involves the use of microgrooved surfaces which retain the advantages of pyramidally textured surfaces while avoiding some disadvantages of the latter. The approach results in a 5–6% improvement in cell short‐circuit current density for cells fabricated on 0.1 and 0.2 &OHgr; cm ( ptype) substrates. This results in an energy conversion efficiency for these devices above 20% under standard terrestrial test conditions (AM1.5, 100 mW/cm2) for the first time.

ISSN:0003-6951    

DOI:10.1063/1.96799

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new technique is described whereby one can extract the nonlinear photothermal properties of a sample in photothermal microscopy. The basic scheme relies on chopping a pump heating beam at &ohgr; and detecting the temperature variation of the sample using a linear temperature sensor (in our case a mirage detector) tuned to 2&ohgr;. Harmonic images of cracks and other samples show very high contrast when compared with the fundamental image.

ISSN:0003-6951    

DOI:10.1063/1.96800

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We report on controlled boron doping of silicon molecular beam epitaxy (MBE) films by two techniques: sublimation of saturated boron‐doped silicon from a boron nitride crucible and evaporation of B2O3from a tungsten crucible. Both methods were performed with the simultaneous evaporation of undoped silicon from an electron beam source. Sharp doping profiles and constant evaporation rates were obtained for both methods. Doping levels between 2×1017and 1.5×1020cm−3were realized. The evaporations require only relatively low temperatures: 700–1150 °C for B2O3and 1000–1400 °C for subliming silicon. These results make it possible to replace gallium as thep‐type evaporative dopant in silicon MBE with the more desirable boron without using ion imbedding or a very high crucible temperature.

ISSN:0003-6951    

DOI:10.1063/1.96801

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The nitrogen effect on enhancement of oxygen precipitation in Czochralski‐grown silicon wafers has been investigated by means of a preferential chemical etching technique and secondary ion mass spectroscopy. The precipitate enhancement is evident in an oxygen out‐diffused region in which oxygen precipitation does not normally occur. Incorporation of the nitrogen atoms in substitutional sites to generate very stable microdefects in Czochralski‐grown silicon crystals can explain the nitrogen effect on oxygen precipitation.

ISSN:0003-6951    

DOI:10.1063/1.96564

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

An analysis of conductance transients in field‐effect transistors for small values of drain‐source voltage is presented which enables absolute values of trap concentration to be evaluated. The relationships use parameters which can be easily measured as distinct from the estimated values of mobility profiles used in previously published calculations. Excellent quantitative agreement between capacitance and conductance results on large area gallium arsenide field‐effect transistors has been obtained. In addition, conductance deep level transient studies have demonstrated that the method of measurement and analysis can be used for micron and submicron devices which are much too small for capacitive measurements.

ISSN:0003-6951    

DOI:10.1063/1.96565

出版商:AIP    

年代:1986

数据来源: AIP