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  • 1
    Electronic Resource
    Electronic Resource
    Ultrafast carrier dynamics at a metal-semiconductor interface (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6831-6838 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The ultrafast carrier dynamics in the high electric field at an Au-GaAs interface has been studied experimentally as well as theoretically. The photoluminescence decay time is related directly to the carrier sweepout from the GaAs depletion region, i.e., to the time needed for photoexcited electrons and holes to leave this region. This decay time has been found to increase drastically with laser input power, ranging from a few picoseconds at low excitation to values of 10–20 ps at high excitation. These results indicate a significant retardation of the sweepout, which cannot be explained by intervalley scattering and space-charge effects. From our Monte Carlo calculations it has been found that the applied electric field collapses totally almost instantaneously after laser excitation due to the enormous excess of photoexcited charges. The sweepout only recovers after some time needed to recharge the device. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363749
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  • 2
    Electronic Resource
    Electronic Resource
    Electrorefraction in strained InGaAs/InP chopped quantum wells: Significance of the interface layers (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 2331-2335 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a model for electrorefraction based on the quantum confined Stark effect (QCSE) in strained InGaAs/InP chopped quantum wells (CQWs) consisting of three 27 Å InGaAs wells separated by 15 Å InP barriers. The model fully takes into account the influence of the thin interface layers around each well. We experimentally verify the model on a InGaAs/InP CQW which combines a large 60 meV QCSE redshift at 11.7 V bias with waveguide transparency at 1.55 μm, which is two times larger than in a InGaAsP quaternary well. The calculated electroabsorption spectra of the CQWs are in good agreement with experiment. We finally applied the Kramers–Kronig transformations for calculating the switching voltage in a Mach–Zehnder switch employing CQWs in the phase shifting section. The model was found to be in good agreement with experiment for both polarizations. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372183
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  • 3
    Electronic Resource
    Electronic Resource
    Dislocations in mismatched layers of GaAsxP1−x in between GaP as observed by low-temperature cathodoluminescence: Part I. Grown on (001) oriented substrates. (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 1660-1666 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The possibility of growing lattice-mismatched layers and quantum wells becomes more and more interesting for the fabrication of devices. For device performance it is necessary to control the formation of misfit dislocations within the mismatched layers. It is therefore essential to study the onset of misfit dislocations versus amount of mismatch and layer thickness. A preliminary cathodoluminescence (CL) investigation, performed on layers of GaAsxP1−x mismatched to GaP barriers, was presented [A. Gustafsson, J. Jönsson, M. Gerling, M. R. Leys, M.-E. Pistol, L. Samuelson, and H. Titze, Inst. Phys. Conf. Ser. No 100, 771 (1989)]. In this paper the critical thickness with respect to the composition, x, in GaAsxP1−x, is studied from a determination of the onset of the formation of dislocations as observed in the monochromatic CL images. The experimental values of the critical thickness are compared to theoretical predictions for the critical thickness, according to different theories. The best agreement is found with the mechanical equilibrium theory, which assumes that the barrier for the formation of dislocations is negligible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349533
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  • 4
    Electronic Resource
    Electronic Resource
    Use of luminescence for the evaluation of stoichiometry in epitaxial growth (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 73-74 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence measurements are described through which details of the stoichiometric conditions which have prevailed on the surface of gallium phosphide (GaP) during growth have been revealed. This ability to probe the balance of the constituents on the growing surface is obtained from tracing the relative occurrences of excitonic peaks which are due to defects on the two sublattices of the binary tetrahedral material. The information on the optimization of the stoichiometry is found to correlate well with morphological evaluation of perfection of the epitaxial growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101758
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of the sign of misfit strain on the dislocation structure at interfaces of heteroepitaxial GaAsxP1−x films (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 2414-2416 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: It was shown, with the use of transmission electron microscopy, that the dislocation structure at interfaces of heteroepitaxial GaAsxP1−x films is dependent on the sign of the misfit strain. Under tensile strain the interface contains a square grid network of both perfect and partial misfit dislocations. The dislocations are straight and exist predominantly along 〈110〉 directions. This configuration of misfit dislocations is consistent with the nucleation of partial dislocations in tensile strained films. The compressive interface also contains a network of misfit dislocations many of which have curved segments. This indicates that a cross slip mechanism has occurred that is only possible with a perfect dislocation movement. This result supports the nucleation of perfect dislocations in films under a compressive strain. The different structural characteristics of the tensile and compressive systems can play a significant role in subsequent processing or devices made from them.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100246
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  • 6
    Electronic Resource
    Electronic Resource
    X-ray interference effect as a tool for the structural investigation of GaInAs/InP multiple quantum wells (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 3630-3637 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present x-ray diffraction (XRD) investigations of the structure of nominally lattice-matched GaInAs/InP multiple quantum well (MQW) structures grown by chemical beam epitaxy (CBE). To obtain information about the individual MQW layers and the interface structure we make use of the x-ray interference effect between two layers of equal lattice constant but different layer thickness separated by ultrathin strained (interfacial) layers. This effect predicted by the dynamical diffraction theory provides a powerful tool to quantitatively investigate ultrathin single quantum well structures and monolayer thin interfaces as well as MQW structures. For a given switching sequence during CBE growth, we determine the interface structure of GaInAs/InP MQW structures within the limits given by XRD theory. Additionally we found that an As gradient from the GaInAs quantum well layers into the InP barrier layers is present. The influence of the substrate off-orientation, the growth rate, and the group V flux in the InP barriers on the total amount of strain incorporated into the InP layers is shown. The obtained results indicate that the mechanism of As incorporation into InP layers is similar to the mechanism observed for the As incorporation into (qua)ternary GaxIn1−xAsyP1−y layers. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366582
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  • 7
    Electronic Resource
    Electronic Resource
    Interfacet surface diffusion in selective area epitaxy of III–V semiconductors (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 2197-2199 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this letter, we discuss the interfacet diffusion of group-III species from {111} B facets to the (100) plane in planar selective area epitaxy. In general, this leads to enhanced vertical growth at the edges of the (100) surface. From such edge profiles, several groups have extracted adatom "diffusion lengths" of ∼1 μm. This is a factor of 100 larger than reported diffusion lengths obtained by reflective high energy electron diffraction, scanning tunneling microscopy, or growth-rate analysis. We show that these values are severely overestimated and that edge profiles only give information on the propagation velocity of macrosteps. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123799
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  • 8
    Electronic Resource
    Electronic Resource
    Andreev reflection at superconducting contacts to GaAs/AlGaAs heterostructures (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 2079-2081 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Highly transmissive ohmic contacts to the two-dimensional electron gas in GaAs/AlGaAs heterostructures have been made. For these contacts, which are of μm scale, a newly developed process of Ti/Sn evaporation and diffusion has been used. Devices consisting of these superconducting contacts combined with gate structures have shown clear evidence for the occurrence of Andreev reflection. Moreover a marked effect of the gate voltage on the dV/dI−V characteristics has been found, which proves that superconductivity has been induced into the semiconductor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.110598
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  • 9
    Electronic Resource
    Electronic Resource
    Aluminium layers as nonalloyed contacts to p-type GaAs (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 1234-1236 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the electrical characteristics of a metallic aluminum layer, deposited on top of heavily doped p-type GaAs, as a means of fabricating nonalloyed ohmic contacts to epitaxial semiconductor structures. The aluminum layer was deposited immediately after growth by molecular beam epitaxy (MBE) of a beryllium-doped GaAs layer, i.e., without exposing the sample to air, or by deposition of an aluminum layer on the same sample in conventional vacuum evaporation equipment. Both types of structures were characterized via the transmission line model (TLM) to obtain the contact resistivity of such nonalloyed ohmic contacts. It appears that planar tunneling contacts grown entirely in an MBE process show contact resistance values which are comparable to alloyed contacts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109782
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  • 10
    Electronic Resource
    Electronic Resource
    SIMS analysis of AlxGa1-xas/gaas layered structures grown by metal-organic vapour phase Epitaxy (1986)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 9 (1986), S. 303-308 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: For AlxGa1-xAs/GaAs layered structures, grown by MOVPE, abrupt interfaces in the order of one atomic distance were observed. These structures are well suited to serve as test samples for studying the influence of bombardment conditions on the quality of SIMS depth profiles. The results of such a study are presented and it is shown that depth profiles can be obtained with a depth resolution of about 25 Å. It was found that beyond the interface secondary ion signals decrease exponentially; from the variation of the slope of this exponential decay as a function of primary ion energy it can be concluded that depth resolution is determined by a purely collisional mixing process. From this type of data we can derive a minimal layer thickness in AlxGa1-xAs/GaAs quantum well structures for which quantitative SIMS analysis of the Al content is possible.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740090507
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