摘要:

The photoresponse to a short optical pulse of a GaAsp‐njunction containing an undoped asymmetric GaAs/AlAs superlattice is reported. The response to a light pulse of <400 fs duration has been measured and a rise time of 80 ps is observed. The trailing edge of the response exhibits a long time tail, which is thought to be dominated by the time taken to tunnel through the thickest barrier, being the &Ggr;‐&Ggr; separation of the GaAs and AlAs of a 3‐nm barrier.

ISSN:0003-6951    

DOI:10.1063/1.97490

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Several superlattice structures, grown by molecular beam epitaxy, have been used to reduce the density of threading dislocations originating from the GaAs substrate. Results clearly indicate that compared to epitaxial layers grown directly on GaAs substrates, a GaAs‐InxGa1−xAs superlattice (x<0.12) reduces the dislocations by approximately two orders of magnitude. Transmission electron microscopy, electron beam induced current, and etch pit density have been used to characterize the effectiveness of using superlattice buffer layers for the reduction of defects in GaAs epilayers.

ISSN:0003-6951    

DOI:10.1063/1.97631

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A continuousp‐type GaAs epilayer has been deposited on ann‐type sawtooth GaAs surface using metalorganic chemical vapor deposition. A wet chemical etching process was used to expose the intersecting (111)Ga and (1¯1¯1)Ga planes with 6 &mgr;m periodicity. Charge collection microscopy was used to verify the presence of thepnjunction thus formed and to measure its depth. The ultimate goal of this work is to fabricate a V‐groove GaAs cell with improved absorptivity, high short‐circuit current, and tolerance to particle radiation.

ISSN:0003-6951    

DOI:10.1063/1.97491

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We propose a new all‐optical time‐of‐flight method which provides transport properties like the average carrier velocity and diffusivity from measurements of the flight duration in semiconductor materials sandwiched between two quantum wells. The method is capable of very high spatial and temporal resolution and is demonstrated by time‐of‐flight experiments in GaAlAs.

ISSN:0003-6951    

DOI:10.1063/1.97492

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

No correlation was found between the stress in hydrogenated amorphous silicon films and the light‐induced effect, as measured by the photoconductivity. An equation is derived for calculation of the external stress applied to a film. The light‐induced degradation in a ‘‘zero‐stress’’ film (one removed from the substrate) was shown to be equivalent to that of an as‐deposited film.

ISSN:0003-6951    

DOI:10.1063/1.97493

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The surface structures that result from the adsorption of Te on (100) GaAs have been shown to affect the orientation of CdTe films on GaAs. Two structures are described here. A low‐temperature (6×1) surface leads to (100) film growth. At 580 °C, a new surface results which is characterized by ordering along directions 60° from [011¯] and [01¯1], and leads to (111) growth of CdTe. Both surface structure and the interaction of the group II element with the surface are believed to be important in determining the orientation of the film.

ISSN:0003-6951    

DOI:10.1063/1.97632

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Annealing of metastable dangling bond defects in light‐soaked undoped hydrogenated amorphous silicon (a‐Si:H) is investigated in samples which have been illuminated at different temperatures. Based on a monomolecular annealing model, the distribution of activation energies is determined. The annealing distribution narrows and shifts to higher energies as the temperature during illumination is increased.

ISSN:0003-6951    

DOI:10.1063/1.97494

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Shubnikov–de Haas, quantum Hall effect, and cyclotron resonance measurements revealed the existence of a high mobility, two‐dimensional electron gas at the Ga0.47In0.53As/InP heterointerface grown by chemical beam epitaxy. Enhanced electron mobilities were as high as ∼130×103cm2/V s at 4.2 K. A striking feature in the data which also indicates that the sample is of high quality is the large number of Shubnikov–de Haas oscillation periods observed. Oscillations were observable up to a Landau filling factor of around 50, corresponding to a Landau level index of 25.

ISSN:0003-6951    

DOI:10.1063/1.97495

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We report the growth and characterization of ultrapure InP using trimethylindium and phosphine by atmospheric pressure organometallic vapor phase epitaxy (APOMVPE). The 77 K mobility of 131 000 cm2 /V s is the highest ever obtained by APOMVPE and among the highest ever measured for InP using any growth technique. The low‐temperature photoluminescence measurements reveal that impurity reduction occurs at higher growth temperatures.

ISSN:0003-6951    

DOI:10.1063/1.97496

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

In0.53Ga0.47As/ In0.52Al0.48As single quantum well structures grown by molecular beam epitaxy were pulse annealed by a halogen lamp to determine the stability of their optical properties after such thermal treatment. The annealing time and temperature were 5 s and 650–850 °C, respectively. The shift in energy of the main peak in the low‐temperature photoluminescence spectra was modeled by considering Al‐Ga interdiffusion at the heterointerface and solving the appropriate Schro¨dinger equation for this region. The estimated interdiffusion constantsDare ∼10−16–10−15cm2/s in this temperature range, which are almost three orders higher than the corresponding values reported for GaAs/ AlxGa1−xAs. For longer annealing times, up to 30 min, the linewidth (full width at half‐maximum) of the excitonic transition in the 11 K photoluminescence spectrum continuously decreased from 12.5 to 7.7 meV, while the intensity maintained a high value.

ISSN:0003-6951    

DOI:10.1063/1.97497

出版商:AIP    

年代:1986

数据来源: AIP