Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Exciton luminescence in Si1−xGex/Si heterostructures grown by molecular beam epitaxy (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 2790-2805 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Coherent Si1−xGex alloys and multilayers synthesized by molecular beam epitaxy (MBE) on Si(100) substrates have been characterized by low-temperature photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). Phonon-resolved transitions originating from excitons bound to shallow impurities were observed in addition to a broad band of intense luminescence. The broad PL band was predominant when the alloy layer thickness was greater than 40–100 A(ring), depending on x and the strain energy density. The strength of the broad PL band was correlated with the areal density (up to ∼109 cm−2) of strain perturbations (local lattice dilation ∼15 A(ring) in diameter) observed in plan-view TEM. Thinner alloy layers exhibited phonon-resolved PL spectra, similar to bulk material, but shifted in energy due to strain and hole quantum confinement. Photoluminescence excitation spectroscopy, external quantum efficiency, time-resolved PL decay, together with the power and temperature dependence of luminescence intensity, have been used to characterize Si1−xGex/Si heterostructures exhibiting both types of PL spectra. The role of MBE growth parameters in determining optical properties was investigated by changing the quantum well thickness and growth temperature. The transition from phonon-resolved, near-band-gap luminescence in thin layers to the broad PL band typical of thick layers is discussed in terms of a strain energy balance model which predicts a "transition thickness'' which decreases with increase in x.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354628
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Intense photoluminescence between 1.3 and 1.8 μm from strained Si1−xGex alloys (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 1037-1039 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Intense photoluminescence (PL) from strained, epitaxial Si1−xGex alloys grown by molecular beam epitaxy is reported with measured internal quantum efficiencies up to 31% from random alloy layers, single buried strained layers, and multiple quantum wells. Samples deposited at ∼400 °C exhibited low PL intensity, whereas annealing at ∼600 °C enhanced the intensity by as much as two orders of magnitude. This anneal treatment was found to be optimal for removal of grown-in defect complexes without creating a significant density of misfit dislocations. PL peak energies at 4.2 K varied from 620 to 990 meV for Ge fractions from 0.53 to 0.06, respectively. Efficient PL was due to exciton accumulation in the strained Si1−xGex layers of single and multiple quantum wells, where the band gap was locally reduced. Optical transitions associated with the PL occurred without phonon assistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.103558
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Growth and band gap of strained 〈110〉 Si1−xGex layers on silicon substrates by chemical vapor deposition (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 76-78 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report chemical vapor deposition growth of strained Si1−xGex alloy layers on 〈110〉 Si substrates. Compared to the same growth conditions on 〈100〉 substrates, a slightly lower Ge composition and a much lower growth rate was observed. From photoluminescence measurements, the band gap of these films for 0.16≤x≤0.43 is evaluated and compared to theory. Finally, a surprisingly large "no-phonon'' replica line strength ratio was observed as compared with that observed in 〈100〉 layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113079
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Luminescence origins in molecular beam epitaxial Si1−xGex (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 61 (1992), S. 690-692 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Interstitial-type features smaller than ∼1.5 nm and in areal densities up to 7×108 cm−2 have been identified as the origin of a broad photoluminescence (PL) band from thick, fully strained layers of Si1−xGex alloys grown by molecular beam epitaxy. The strong PL band was predominant when the alloy layer thickness was greater than 4–10 nm, depending on x and the growth temperature. Thinner alloy layers exhibited phonon-resolved transitions originating from shallow dopant bound excitons, similar to bulk material but shifted in energy due to strain and hole quantum confinement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.107823
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Mapping electrically active dopant profiles by field-emission scanning electron microscopy (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 1593-1595 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Secondary electron (SE) image contrast from p-type silicon has been studied using field-emission scanning electron microscopy (FE-SEM). Cross-sectional FE-SEM images of boron-doped silicon heterostructures have been compared with atomic concentration and free carrier profiles measured by secondary-ion mass spectroscopy and electrochemical capacitance-voltage profiling, respectively. FE-SEM image contrast due to dopants has been shown to be electronic in origin. Since electrically active dopant species contribute solely to SE image contrast, FE-SEM can be effectively used to map electrically active dopant profiles in two dimensions with a sensitivity as low as 1016 cm−3. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117041
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Misfit strain relaxation in GexSi1−x/Si heterostructures: The structural stability of buried strained layers and strained-layer superlattices (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 1850-1862 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The critical thickness-strain relationships for buried strained layers and strained-layer superlattices (SLSs) are derived using an energy balance model. Relaxation of the entire heterostructure and individual strained layers by both 60° type a/2〈011〉 and pure edge dislocations is considered. GexSi1−x/Si heterostructures designed to investigate the stability regimes predicted by the model were grown by molecular-beam epitaxy. The extent of relaxation and the detailed dislocation structure were assessed in annealed structures by x-ray rocking curve analysis, transmission electron microscopy, and Nomarski microscopy of etched samples. Comparison of metastable as-grown and post-growth annealed microstructures revealed the evolution of misfit dislocation structure as equilibrium was approached on annealing in the temperature range 600–900 °C. The predominant relaxation mechanism for most GexSi1−x/Si heterostructures was by 60° a/2 〈011〉 misfit dislocations at the first strained-layer/substrate interface. However, for SLSs with strained layers exceeding their individual critical thickness, pairs of dislocations and prismatic loops on (011) planes were observed entrained within the GexSi1−x layers. The agreement between experimentally observed relaxation behavior and the critical thickness versus strain predictions of the energy balance model is remarkable. Superlattices and buried strained layers were found to be only slightly more stable than an uncapped strained layer of the equivalent strained-layer thickness. Interdiffusion was observed at annealing temperatures above 800 °C; annealing at 900 °C for 30 min was sufficient to eliminate the strain and composition modulation in a superlattice with a 55-nm period and x=0.25. The relative influence of the various strain relaxation mechanisms is discussed for the alloy range 0〈x〈1 and for geometries with strained-layer dimensions varying from 0.8 to ∼500 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.345613
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    A new gastric juice peptide, BPC. An overview of the stomach-stress-organoprotection hypothesis and beneficial effects of BPC
    Amsterdam : Elsevier
    Journal of Physiology-Paris 87 (1993), S. 313-327 
    Details
    ISSN: 0928-4257
    Keywords: BPC 157 ; BPC organoprotection ; link-stomach ; new gastric juice peptide BPC ; organoprotection ; organoprotective agents ; organoprotective mediator ; pentadecapeptide ; stomach organoprotective stress response
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0928-4257(93)90038-U
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Über eine eigenartige normal vorkommende Bildung an der unteren Nasenmuschel des Menschen (1940)
    Springer
    Anatomy and embryology 110 (1940), S. 597-633 
    Details
    ISSN: 1432-0568
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung An vorderen Abschnitt der unteren Nasenmuschel wird eine besondere regelmäßig vorkommende Bildung beschrieben, die darin besteht, daß die Muschelwand in dieser Partie eine eigene Krümmung, eine Ausbiegung nach Art eines Luftschraubenarmes, medialwärts erhält. Um dieses auffallendste Merkmal der Bildung zum Ausdruck zu bringen, wird für sie die BezeichnungPars evoluta zum Vorschlag gebracht. Ihre Ursache ist in einer medialwärts gerichteten schrägen Abknickung der vorderen Knochenpartie dem übrigen Muschelkörper gegenüber zu suchen. Ihre Bedeutung liegt darin, daß durch die Ausbiegung der Muschelwand in ihrem Gebiete der untere Nasengang an der Stelle eine Erweiterung erfährt und ein flächenhaftes Anlegen der Muschel an die Maxilla vermieden wird. Ihre Gestalt im einzelnen, ihre Entwicklung und ihre Bedeutung für die Verfestigung des Muschelknochens wird beschrieben, sowie weitere Formmerkmale dieses Knochens, des unteren Nasenganges und der Crista conchalis des Oberkiefers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02119091
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Zur Entwickelungsgeschichte des Ductus endolymphaticus beim Menschen (1915)
    Springer
    Anatomy and embryology 52 (1915), S. 699-716 
    Details
    ISSN: 1432-0568
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02041239
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Microscopy in solid state science (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 299-315 
    Details
    ISSN: 1059-910X
    Keywords: STEM ; PEELS ; HAADFI ; Nanolithography ; Super-resolution ; STM ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The Microstructural Physics group at the Cavendish Laboratory is actively involved in a considerable number of research projects which cover a broad range of materials science. In this paper, we describe briefly several such projects, with particular emphasis given to the application of parallel-detection electron energy loss spectroscopy (PEELS) on a scanning transmission electron microscope (STEM) to the analysis of materials such as stainless steels, catalysts, and high temperature superconductors. In addition, we describe a number of related projects that are currently being carried out in the group, particularly those which utilise and develop novel STEM imaging and analytical techniques. © 1993 Wiley-Liss, Inc.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070240404
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...