摘要:

The profile distribution and lattice location of Zn atoms after laser irradiation of ion implanted Si and Ge substrates have been determined by ion beam analysis techniques. In Si the implanted Zn is completely zone refined to the surface whilst in Ge considerable trapping and supersaturation are obtained. Zn is a fast interstitial diffuser in Si and a slow substitutional diffuser in Ge. This result confirms the kinetic trapping model in which the solid phase diffusivity of the considered dopant plays an important role in determining the velocity at which the interfacial segregation coefficient deviates from the equilibrium value.

ISSN:0003-6951    

DOI:10.1063/1.93828

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Amorphous silicon thin films on glass substrates were crystallized by a 4‐&mgr;s light pulse from a plasma arc. Explosive crystal growth from nucleation centers was observed at 4.6 J/cm2. Large silver‐shaped streaks (0.7 mm×50 &mgr;m) were produced. Conductivity changed by six orders of magnitude and the flashed samples gave high photoconductivity. Growth patterns were different near the threshold value of 3.1 J/cm2.

ISSN:0003-6951    

DOI:10.1063/1.93829

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The deposition rate, electronic and optical properties of hydrogenated amorphous silicon films prepared from rf glow discharge decomposition of disilane (Si2H6) diluted in helium have been measured. These films show excellent electrical and optical properties and, most importantly, a high deposition rate coupled with satisfactory solar cell application was realized for the first time. At a deposition rate of 11 A˚/s, 5.47% and 6.5% conversion efficiencies were obtained with a first trial ofn‐i‐ptype solar cells deposited on SnO2/ITO glass and metal substrates, respectively.

ISSN:0003-6951    

DOI:10.1063/1.93830

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The degradation of 1.3‐&mgr;m InP/InGaAsP light‐emitting diodes (LED’s) with misfit dislocations was investigated. Initially, the misfit dislocations were found to be present only in thep‐InP confining layer and they thus showed weak (∼1%) contrast in the electroluminescence (EL) image of the light‐emitting region. Without bias, no degradation of the LED’s was measured after 103h at 200 °C. After 103h at 20 °C and 8 kA/cm2, a previous study found that InP/InGaAsP LED’s containing misfit dislocations did not degrade. However, our study showed that the lifetime of the LED’s varied inversely with the third power of the current density. In the degraded LED’s, the misfit dislocations showed stronger (∼50%) contrast in the EL image, suggesting that they played a significant role in the device degradation. In these devices, misfit dislocations were found not only in thep‐InP confining layer but also in the light‐emitting region of the active layer. The degradation of InP/InGaAsP LED’s with misfit dislocations is thus consistent with the mechanism of nonradiative recombination enhanced growth of the misfit dislocations into the active layer. For our device structure, wafers with &Dgr;a/a≲0.05% lattice mismatch are free of misfit dislocations and thus ensure reliable device operation at high current densities.

ISSN:0003-6951    

DOI:10.1063/1.93831

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Deep impurity levels in metastable (GaAs)1−xGe2xalloys are predicted to bifurcate as functions ofxat the alloy order‐disorder transition composition.

ISSN:0003-6951    

DOI:10.1063/1.93832

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Photoelectrochemical measurements have been carried out onp‐Si electrodes which contained islands of Pb, Cd, Au, Ni, Co, and Pt. These islands cause the photocurrent density of some of the Si systems to increase greatly (10×) in the middle region of the photocurrent potential curve. A plot of the change in potential observed for this region against log i0for the dark hydrogen evolution on the metals concerned is linear with a slope close to that expected for a rate determining step at themetal‐solution interface.

ISSN:0003-6951    

DOI:10.1063/1.93833

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Si overlayers have been grown under ultrahigh vacuum conditions on GaP(100) single crystals by means of molecular beam epitaxy. For growth temperatures of 300 °C and higher (2×1) low‐energy electron diffraction patterns of the Si overlayers were seen at all overlayer thicknesses produced (8–10 000 A˚). By means of Auger electron spectroscopy segregation of P and Ga on top of the grown Si surface was measured. With Rutherford backscattering using ion channeling we found Si minimum channeling yields of 3% in the GaP:Si(100) heterostructures, which corresponds well to the yield of pure monocrystalline (100) Si. Two methods are described to eliminate the Ga and P segregation.

ISSN:0003-6951    

DOI:10.1063/1.93834

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We have developed a sensitive, ultrahigh speed photodetector which has a structure of a modulation‐doped AlxGa1−xAs/GaAs field‐effect transistor. In spite of a large gate‐drain spacing of >8 &mgr;m and a gate length of >20 &mgr;m, this detector exhibited a rise time of 12 ps and a full width at half‐maximum of 27 ps. When tested by a 8200‐A˚ GaAs injection laser, the detector showed an ac (>20 MHz) external quantum efficiency of >630%, i.e., 9 times more sensitive than apinphotodiode. In view of its high sensitivity, ultrahigh speed, and compatibility with modulation‐doped field‐effect transistors, this detector has promise for a variety of high‐speed optical applications.

ISSN:0003-6951    

DOI:10.1063/1.93835

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

It is shown that the percolation model previously proposed to explain the high concentration diffusion of phosphorus in Si holds also in the case of arsenic. Suitable numerical values of the parameters are derived, and it is shown that the model allows the simulation of arsenic diffusion in a wide range of experimental conditions.

ISSN:0003-6951    

DOI:10.1063/1.93836

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We consider the combined effect of shot and thermal noise on (i) the stationary distribution of fluctuations about the nonzero voltage state of an underdamped hysteretic Josephson junction, and (ii) the noise induced transition rate from the nonzero voltage to the zero voltage state. We find that the distribution is nonsymmetric in that the positive voltage fluctuations are more probable than the negative ones. We also find that the transition rates are larger than those due to thermal noise alone.

ISSN:0003-6951    

DOI:10.1063/1.93837

出版商:AIP    

年代:1983

数据来源: AIP