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
    Growth modes and microstructures of ZnO layers deposited by plasma-assisted molecular-beam epitaxy on (0001) sapphire (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 5115-5119 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Transmission electron microscopy and high resolution x-ray diffraction are used to characterize defects in ZnO layers grown by plasma-assisted molecular-beam epitaxy on (0001) sapphire. Two- and three-dimensional types of growth modes are described and the observed mosaic structure is analyzed in each case. It is found that two-dimensional layers exhibit a roughness as low as 6 nm. Their subdomains have small lateral coherence lengths and a mean in-plane misorientation of ±0.4°, leading to an important dislocation density of 1–4×1010 cm−2. On the contrary, it is demonstrated that, through numerous interactions between dislocations, the three-dimensional growth mode leads to a better structural quality with a larger lateral coherence length and a smaller in-plane mosaic spread of ±0.07°. The total dislocation density is consequently reduced by 1 order of magnitude down to 3–5×109 cm−2 and the radical modification of the structure results in a change of the dislocation distribution. Our results thus demonstrate that two-dimensional growth mode and low full width at half maximum for symmetric x-ray diffraction are a not reliable indicator of a good structural quality. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1412572
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Reduction mechanisms for defect densities in GaN using one- or two-step epitaxial lateral overgrowth methods (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 4175-4181 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A transmission electron microscopy study of the reduction mechanisms for defect densities in epitaxial lateral overgrown (ELO) GaN films is presented. In the standard one step ELO, the propagation of defects under the mask is blocked, whereas the defects in the window regions thread up to the surface. We propose an alternative two step ELO method. In a first step, dislocations close to the edge of the (0001) top facet bend at 90°, thereby producing a drastic reduction in the density of defects above the window. After the coalescence, induced by lateral growth in a second step, dislocations are mainly observed in the coalescence boundaries. The density of defects is decreased to 2×10−7 cm−2 over the entire surface and areas nearly 5 μm wide with 5×106 cm−2 dislocations between the center of the windows and the coalescence boundaries are obtained. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373048
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Lattice relaxation and three-dimensional reflection high-energy electron-diffraction analysis of strained epitaxial Co/Mn superlattices (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 2817-2824 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In situ observations of reflection high-energy electron diffraction (RHEED) are used to study the structure and growth of epitaxial Co/Mn superlattices on hcp (0001) Ru buffer layers. Mn deposited on fcc (111) or hcp (0001) Co presents a singular growth behavior which can be interpreted as an incoherent growth with compressive stresses perpendicular to the surface. Moreover, the Mn structure is found to switch from a sixfold in-plane symmetric 1×1 structure, which probably corresponds to strained fcc γ-Mn, to a sixfold in-plane symmetric (square root of)3×(square root of)3−30° structure with in-plane lattice parameter a=4.69 A(ring). This structural change occurs at a critical thickness of 5–6 monolayers, after the partial relaxation of the Mn in-plane lattice parameter. An analysis of the three-dimensional contribution to the RHEED patterns shows that the (square root of)3×(square root of)3−30° structure is probably identical to the Cu2Mg Laves phase which in turn closely resembles the α-Mn phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357516
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Ferromagnetic resonance determination of fcc→hcp structural change in epitaxial Co/Mn superlattices : 38th Annual Conference on Magnetism and Magnetic Materials (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 5601-5603 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A series of epitaxial [Co24 A(ring)MntMn]12 superlattices (3.2 A(ring)≤tMn≤32 A(ring)) was grown on hcp(0001) Ru buffer layers by ultrahigh vacuum e-beam evaporation. Ferromagnetic resonance has shown that for samples with 3.2 A(ring)≤tMn≤12 A(ring), the cobalt layers are predominantly fcc and almost perfectly fcc for the sample having the thinnest Mn thickness [Co24 A(ring)/Mn3.2 A(ring)]12. For samples with greater Mn thickness (tMn(approximately-greater-than)12 A(ring)), the cobalt layers are predominantly hcp with structural defects corresponding either to large inclusions of fcc Co or stacking faults.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355654
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Molecular-beam epitaxy of gallium nitride on (0001) sapphire substrates using ammonia (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 1379-1383 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ammonia is used for growing undoped GaN layers by gas source molecular-beam epitaxy on c-plane sapphire substrates. The growth mode is layer by layer as shown by the observation of reflection high-energy electron diffraction intensity oscillations. The structural quality is studied by x-ray diffraction, transmission electron microscopy, and Raman spectroscopy. Low-temperature photoluminescence (PL) and reflectivity demonstrate intrinsic excitonic emission. Room-temperature PL exhibits a strong band-edge intensity and a weak deep-level emission, the so-called yellow band. Finally, secondary ion mass spectroscopy is carried out to check the residual impurity levels of Si, C, and O. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366840
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Heteroepitaxial growth of BeSe on vicinal Si(001) surfaces (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 957-959 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The growth of BeSe on vicinal Si(001) substrates has been investigated by molecular beam epitaxy. Reflection high energy electron diffraction was used to study the initial growth mode and the surface structure. Efforts have been done at the early steps of the growth in order to optimize the interface quality. Transmission electron microscopy revealed a BeSe layer relaxed with misfit dislocations and stacking faults that are mainly confined near the heterointerface. These results are promising in view of the growth of Zn0.55Be0.45Se alloy that is lattice matched to silicon. There will be many potential applications of this alloy—in the case of a direct band gap—in the frame of Si-based optoelectronic devices. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.122051
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Epitaxial relationships between GaN and Al2O3(0001) substrates (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 643-645 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: GaN thin layers (200 Å) were grown by gas-source molecular beam epitaxy on c-plane Al2O3 substrates. Transmission electron microscopy reveals that two different epitaxial relationships may occur. The well-known GaN orientation with the c axis perpendicular to the Al2O3 surface and [11¯00]GaN||[112¯0]Al2O3 is observed when the substrate is nitridated prior to the growth. On the other hand, GaN layers deposited on bare Al2O3 surfaces exhibit a different crystallographic orientation: [112¯0]GaN||[11¯00]Al2O3 and [11¯03]GaN||[112¯0]Al2O3. This corresponds to a tilt of about 19° of the c axis with respect to the substrate surface. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118205
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Structural and optical properties of lattice-matched ZnBeSe layers grown by molecular-beam epitaxy onto GaAs substrates (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 3564-3566 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the molecular-beam epitaxy of ZnBeSe ternary alloys lattice matched onto GaAs substrates. We demonstrate that these alloys can be grown with a high structural perfection. X-ray linewidths down to 27 arcsec are obtained even though the growth is carried out on bare substrates. Transmission electron microscopy reveals the high quality of the interface. Photoluminescence spectra of undoped layers are dominated by free-exciton recombinations. The excitonic gap is determined to be 2.863 eV at 9 K. Finally, high carrier concentrations are obtained for both n-type and p-type doping. These results are promising in view of fabricating laser diodes with this material system. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.119234
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    GaInN/GaN multiple-quantum-well light-emitting diodes grown by molecular beam epitaxy (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 3616-3618 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: GaInN and GaN were grown by molecular beam epitaxy on c-plane sapphire using NH3. 9 K photoluminescence performed on both GaInN thin layers and GaInN/GaN multiple-quantum wells (MQWs) exhibits narrow emission (∼50 meV linewidths). Transmission electron microscopy images show sharp GaInN/GaN interfaces and homogeneous GaInN layers. Strong indium surface segregation is also evidenced. Light-emitting diodes were fabricated from 5×GaInN (25 Å)/GaN (35 Å) MQW heterostructures. The 300 K electroluminescence yields blue light at 440 nm. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123199
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The effect of the Si/N treatment of a nitridated sapphire surface on the growth mode of GaN in low-pressure metalorganic vapor phase epitaxy (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 1278-1280 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this letter, we studied the effect of the high-temperature Si/N treatment of the nitridated sapphire surface followed by the deposition of a low-temperature GaN nucleation layer on the growth mode of GaN in low-pressure metalorganic vapor phase epitaxy. It was shown that the nucleation layer, initially flat and continuous, converts to wide isolated truncated hexagonal islands having {1–101} facet planes and a top (0001) plane, after heating up to 1150 °C. The coalescence of these GaN islands yields a reduction of the total number of extended defects from the 1010–1011 cm−2 range usually obtained down to the low 109 cm−2 range for the best samples. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.122148
    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...