摘要:

We have undertaken a new set of experiments to investigate the behavior of adsorbed‐impurity induced reconstructions at growth interfaces. We have observed a striking difference in the stability of the B(3)1/2×(3)1/2and Ga(3)1/2×(3)1/2two‐dimensional structures at the interface between Si(111) anda‐Si, and in their segregation behavior during molecular beam epitaxy crystal growth. This leads to a new model of dopant behavior in silicon molecular beam epitaxy.

ISSN:0003-6951    

DOI:10.1063/1.101869

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The nature and behavior of antiphase boundaries in GaAs/Si heterostructures using GaP, GaP/GaAsP, and GaAsP/GaAs strained‐layer superlattices as intermediate layers have been studied by transmission electron microscopy. The antiphase domains are found to be very complicated three‐dimensional polygons consisting of several subboundaries in different orientations. Self‐annihilation of antiphase domains during crystal growth of GaAs on (001) 0.4° off or (001) 2° off Si substrates is directly observed for the first time through plan‐view and cross‐sectional observations. Based on these findings, a mechanism of annihilation of these domains is presented.

ISSN:0003-6951    

DOI:10.1063/1.101870

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Structural investigations of high quality Si/Ge strained‐layer superlattices (SLSs) on [001] oriented Ge substrates prepared by molecular beam epitaxy are presented. Cross‐sectional transmission electron microscopy reveals that a defect‐free superlattice is achieved for a structure composed of a 20‐period sequence of 3 monolayers (ML) Si and 9 ML Ge. High‐resolution lattice images and electron diffraction patterns show that the whole structure is matched to the Ge substrate. Experimental values for the tetragonal deformation of the Si layers within the SLS are in good agreement with theory. An equivalent sample containing 120 periods exceeds the critical thickness for pseudomorphic growth of the SLS and shows the formation of twin lamellae.

ISSN:0003-6951    

DOI:10.1063/1.101871

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Secondary‐ion mass spectroscopy and cathodoluminescence (CL) studies were carried out on GaAs films grown by Ar+laser‐assisted metalorganic molecular beam epitaxy. The Ar+laser irradiation leads to the formation of a 400‐&mgr;m‐diam spot. In the growth temperature range 425–500 °C, the carbon concentration within the spot is maintained at 1017cm−3, while that in the area not irradiated by the laser increases from 1017to 1019cm−3. The process of decomposition of the triethylgallium molecules and the mechanism by which the carbon concentration is maintained by the laser irradiation are discussed in detail. Low‐temperature CL spectra revealed that the CL signal intensity in the selectively grown spot was some ten times greater than that in the area not irradiated by the laser.

ISSN:0003-6951    

DOI:10.1063/1.101872

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A calculation for an effective mass model of a double quantum well structure subjected to a moderate electric field is presented. The behavior of the transitions between energy levels is investigated, allowing prediction of an effective blue shift in the optical spectrum of this simple system. It is suggested that the optimum strategy for obtaining a rapid effect is to reduce the coupling between the heavy hole states.

ISSN:0003-6951    

DOI:10.1063/1.101850

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

On studying the magnetoresistivity of GaAs‐GaInP heterostructures grown by low‐pressure metalorganic chemical vapor deposition in magnetic fields up to 12 T and at liquid‐helium temperatures, we have observed extremely high electron mobilities. Using the persistent photoconductivity effect, by illumination with red light, we reached a mobility of 780 000 cm2/(V s) at an electron density of 4.1×1011cm−2. This high electron mobility is confirmed by cyclotron resonance measurements.

ISSN:0003-6951    

DOI:10.1063/1.101851

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The luminescence of photoexcited carriers far above the band gap of Ga0.47In0.53As is studied with subpicosecond time resolution. In undamaged material the luminescence decays with characteristic times of 2–4 ps in the energy range between 1.9 and 1.4 eV, due to the rapid energy relaxation of electrons and holes far above the band edges. In radiation‐damaged (He+bombarded) material, luminescence decay times as short as 0.9 ps are observed. The luminescence spectra give evidence for extreme nonequilibrium distributions of the photoexcited carriers, caused by the ultrafast recombination, which—in radiation‐damaged samples—is a faster process than energy relaxation.

ISSN:0003-6951    

DOI:10.1063/1.101852

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Carbon incorporation in ZnSe films grown by metalorganic chemical vapor deposition is reported. Secondary‐ion mass spectrometry measurements in ZnSe films grown from methylallylselenide and dimethylzinc show an enhanced carbon accumulation at the interface between ZnSe and GaAs. The carbon incorporation in the bulk ZnSe increases with the VI/II ratio and for a value of VI/II=3–4, the amount of incorporated carbon abruptly jumps to concentrations of 1021cm−3, whereupon the films become polycrystalline. A new shallow peakICat 2.7920 eV dominates the near‐band‐edge low‐temperature photoluminescence spectra of all carbon‐contaminated ZnSe films. The intensity and linewidth ofICincrease with the VI/II ratio in a similar manner to the carbon concentration. This peak is proposed to be due to the radiative decay of excitons bound to a complex defect, which is associated with the presence of carbon in the films.

ISSN:0003-6951    

DOI:10.1063/1.101853

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A new technique is proposed to evaluate the radiation response of metal‐oxide‐semiconductor (MOS) transistors. The method requires that otherwise identicaln‐ andp‐channel transistors be irradiated under the same conditions. Using assumptions similar to those of widely accepted ‘‘single‐transistor’’ methods, standard threshold‐voltage and mobility measurements are combined to accurately estimate threshold‐voltage shifts due to oxide‐trapped charge and interface traps. This approach is verified for several MOS processes. The dual‐transistor method can be applied to devices with much larger parasitic leakage, and at shorter times following a radiation pulse, than subthreshold current or charge‐pumping techniques.

ISSN:0003-6951    

DOI:10.1063/1.101854

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Epitaxial layers of (111) Cd1−xMnxTe (x=0.05) were grown on (111) GaAs substrates by pulsed laser evaporation and epitaxy. A XeCl excimer laser beam was directed at a Cd0.95Mn0.05Te target to produce the vapors necessary for deposition. A simultaneously operating pulse Nd:YAG laser was used to create the overpressure of Cd needed in the growth of stoichiometric films.Insitureflection high‐energy electron diffraction, as well as scanning electron microscopy, energy‐dispersive x‐ray analysis, and photoluminescence study showed that the films had characteristics comparable to the best CdMnTe epilayers grown so far by molecular beam epitaxy or metalorganic chemical vapor deposition.

ISSN:0003-6951    

DOI:10.1063/1.101855

出版商:AIP    

年代:1989

数据来源: AIP