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Presents a study that have grown epitaxial layers of silicon-doped indium-arsenic-antimony by molecular-beam epitaxy on gallium arsenide (GaAs) and GaAs-coated silicon substrates. Absorption coefficient; Use of the fitted value of the Fermi level; Electron concentration.

Focuses on strained single quantum wells composed of gallium arsenide (GaAs)/indium-gallium-arsenic (InGaAs)/GaAs grown by molecular beam epitaxy. Application of photoreflectance by photoluminescence spectroscopy; Empirical equation describing the nonstrained band-gap energy function; Optical properties of the InGaAs/GaAs system.

Presents a study that investigated the growth, structural, electrical and optical characterization of strained triple-quantum-well light emitting diodes. Use of molecular beam epitaxy to grow the heterostructures; Optical performance of the diodes.

Presents a study which analyzed the incorporation of silicon δ doping during the molecular-beam epitaxial growth of gallium arsenide (GaAs) and Al[sub0.25]Ga[sub0.75]As using secondary-ion mass spectroscopy. Overview of studies on the diffusion of the planar layer of silicon dopants in GaAs or AlGaAs; Materials and methods used; Description of the silicon[sub+] depth profiles; Values of diffusion length and coefficients of GaAs.

The epitaxial growth of GaN on Ge is reported. The authors found that direct growth of GaN performs exceptionally well on Ge(111) with plasma assisted molecular beam epitaxy. A streaky reflection high energy electron diffraction pattern is observed during growth. X-ray diffraction showed a rocking curve full width at half maximum of only 371 arc sec for a 38 nm GaN layer and indicates an abrupt interface between the GaN and Ge. Secondary ion mass spectrometry shows limited diffusion of Ga atoms into the Ge substrate and Ge atoms into the GaN layers. Current-voltage measurements show rectifying behavior for n-GaN on p-Ge. Their results indicate that GaN growth on Ge does not require intermediate layers, allowing the Ge substrate to be used as back contact in vertical devices. A p-n junction formed between GaN and Ge can be used in heterojunction devices. [ABSTRACT FROM AUTHOR]

A local structural transition in heavily Fe-doped GaN films related to the magnetic properties has been revealed by fluorescence x-ray absorption fine structure (XAFS) analysis. The structural transition is explained (or considered to be induced) by the change in the degree of hybridization between Fe 3d and N 2p states, which can be evaluated by x-ray absorption near edge structure spectra. The XAFS analysis indicates that the present diluted magnetic semiconductor based on GaN can be fabricated by electron cyclotron resonance microwave plasma-assisted low-temperature molecular-beam epitaxy. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents a study which described the structural and magnetic properties of tauMnAl/Co superlattices epitaxially grown on alas/GaAs by Molecular Beam Epitaxy. Experimental details; Results of the study; Conclusions.

Investigates the molecular beam epitaxial growth of InAsSb on gallium arsenide (GaAs)-coated patterned silicon (Si) substrates. Comparison of the InAsSb epilayer morphology for different substrate conditions; Threaded defect density of the InAsSb layers; Evidence of a regular array of misfit dislocations.

Epitaxial layers of InAs1-xSbx(0≤x≤1) have been grown on GaAs and on GaAs-coated Si substrates by molecular beam epitaxy using tetrameric Sb and dimeric As sources. Room-temperature transmission spectroscopy was used to measure the optical band gap of the InAs1-xSbx layers and the composition was determined by x-ray wavelength dispersive spectroscopy. We obtained shiny morphology InAs1-xSbx layers on GaAs-coated Si, comparable to those grown on GaAs. Our results are very encouraging towards the monolithic integration of InAs1-xSbx long-wavelength infrared detectors with Si charge-coupled devices. [ABSTRACT FROM AUTHOR]

A gallium arsenide film is grown embedded in masked pre-etched wells in silicon vicinal (001) substrates by molecular beam epitaxy. The morphology and crystallinity of the embedded GaAs on Si layers are identical to those of large area GaAs on Si grown on the same wafer, as indicated by the comparison of Nomarski contrast photomicrographs and electron channeling patterns. High-resolution electron microscope images reveal the epitaxial relation of the GaAs/Si interface on the bottom and the sidewall of the wells. On the slope most of the dislocations are restricted to a narrow region near the interface. The same photoluminescent behavior is found for the GaAs deposit in the different silicon environments. This embedded growth technique is suitable for realization of a coplanar GaAs on Si surface. [ABSTRACT FROM AUTHOR]

Structural characterization has been performed on (0001)-GaN epilayers grown on (111)-Ge substrates using plasma assisted molecular beam epitaxy. By combining high-resolution x-ray diffraction, transmission electron microscopy, and scanning transmission electron microscopy, it has been shown that the GaN epilayer consists of misoriented domains. The domains are rotated about the GaN-[0001] (Ge-[111]) zone axis by 8° with respect to each other and by ±4° with respect to the Ge substrate. These domains need to be eliminated to reduce grain boundary defects and improve GaN crystal quality. [ABSTRACT FROM AUTHOR]

We succeeded in growing highly Fe-doped GaN films by solid-source molecular beam epitaxy using an electron-cyclotron-resonance microwave nitrogen plasma. The substrate temperature was in the range of 380-520 °C. The samples were analyzed by x-ray diffraction and transmission electron microscopy, and showed hexagonal (wurtzite) or cubic (zincblende) structure or a mixture of both phases. The Fe concentration was on the order of 10[sup 19] cm[sup -3] and extended x-ray absorption fine structure data show that the Fe is substituting the Ga in GaN. The magnetization measurements as a function of temperature reveal ferromagnetic properties below 100 K for the sample grown at the lowest temperature. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We show the growth of epitaxial NiMnSb(001) thin films, a half-metallic ferromagnet, on GaAs(001) by molecular-beam epitaxy. The Sb content of the films strongly depends on the Sb flux. Sb-deficient films show a reduced magnetization and the formation of a Mn[sub 2]As interface layer. Stoichiometric films exhibit the bulk lattice constant, have a saturation magnetization close to the bulk value, and do not suffer from Mn[sub 2]As formation at the interface. They show in-plane uniaxial anisotropy with nearly square hysteresis loops along the easy axis, which points either along [110] or [11¯0] depending on the growth conditions. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: Early efforts to grow GaN layers on germanium substrates by plasma assisted molecular beam epitaxy led to GaN domains, rotated by 8° relative to each other. Increased insight in the growth of GaN on germanium resulted in the suppression of these domain and consequently high quality layers. In this study the interface of these improved layers is investigated with transmission electron microscopy. The GaN layers show high crystal quality and an atomically abrupt interface with the Ge substrate. A thin, single crystalline Ge3N4 layer is observed in between the GaN layer and Ge substrate. This Ge3N4 layer remains present even at growth temperatures (850°C) far above the decomposition temperature of Ge3N4 in vacuum (600°C). Triangular voids in the Ge substrate are observed after growth. Reducing the Ga flux at the onset of GaN growth helps to reduce the triangular defect size. This indicates that the formation of voids in the Ge substrate strongly depends on the presence of Ga atoms at the onset of growth. However complete elimination was not achieved. The formation of voids in the germanium substrate leads to diffusion of Ge into the GaN layer. Therefore we examined the diffusion of Ge atoms into the GaN layer and Ga atoms into the Ge substrate. It was found that the diffusion of Ge into the GaN layer and Ga into the Ge substrate can be influenced by the growth temperature but cannot be completely suppressed. Our results suggest that Ga atoms diffuse through small imperfections in the Ge3N4 interlayer and locally etch the Ge substrate, leading to the diffusion of Ga and Ge atoms. [ABSTRACT FROM AUTHOR]

Abstract: Heteroepitaxial growth of GaN on Ge(111) by molecular beam epitaxy has previously been reported to be feasible. However, structural characterization revealed that these GaN layers consisted of misoriented domains. In this work, it is shown that the formation of domains can be suppressed by increasing the substrate temperature, decreasing the nitrogen flux or increasing the surface step density by using off-oriented substrates. Hereby, the step flow growth is enhanced with respect to 2D nucleation. The suppression of domains significantly improves the crystal quality of the GaN layer. For 47nm of GaN a (0002) and (101¯2) ω FWHM value of, respectively, 408 and 935arcsec is obtained. [Copyright &y& Elsevier]

Abstract: Many novel applications are foreseen for the InN-containing materials especially when cheap, conductive substrates can be used. In this paper, we report on the growth of pure InN layers on germanium (Ge) (111) substrates. We found that high-quality InN can be grown on Ge(111) with plasma-assisted molecular beam epitaxy when using a thin GaN intermediate layer. On such intermediate GaN layers, 50nm InN layers were grown and analyzed by RHEED, XRD, AFM, Hall and I–V measurements. Additionally, using ellipsometry we could determine that the optical bandgap of these InN layers lies around 0.85eV. Our results indicate that Ge(111) is a promising substrate for vertical conducting devices, with In(Ga)N on top. [Copyright &y& Elsevier]

The use of electron spin in future spintronic applications requires hybrid ferromagnetic/semiconductor structures with well controlled materials properties. Besides the control of the magnetic properties there are strict requirements for the material aspects of these devices: single phase, single crystal, perfect interfaces, defect control. Molecular beam epitaxy (MBE) has been used very successfully over the past 10 years to produce the most interesting spintronic heterostructures. In this paper we review our effort in using MBE to fabricate spintronic materials and heterostructures. We also discuss some aspects of future spintronic devices with the focus on the material aspects of transferring the electron spin information from the magnetic side of the heterostructure into the semiconductor side. [Copyright &y& Elsevier]