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
    Optical and structural properties of ternary alloy AlxGa1−xAs/AlAs multiple-quantum-well structures (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 1512-1520 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The linear and nonlinear optical properties of a series of ternary alloy AlxGa1−xAs/AlAs multiple-quantum-well structures have been investigated and related to the multilayer configuration. The direct energy gap was found to scale with the AlAs mole fraction as predicted by Lee and Yuravel [Phys. Rev. B 21, 659 (1980)] and the band offset ratio to depend on the alloy composition. Exciton absorption bleaching was observed at room temperature and the nonlinear absorption cross sections were estimated for the first two confined excitonic states. Finally, the possibility of achieving optical gain for the type-II band alignment along the growth direction as well as in the layer plane is demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351718
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Structural properties and transport characteristics of pseudomorphic GaxIn1−xAs/AlyIn1−yAs modulation-doped heterostructures grown by molecular-beam epitaxy (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 1790-1797 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Non-lattice-matched GaxIn1−xAs/AlyIn1−yAs modulation-doped heterostructures grown on (100) InP by molecular-beam epitaxy suitable for application in field-effect transistors have been studied. A computer simulation of the x-ray diffraction pattern proves to be necessary to obtain precise information about the structural parameters of the samples. The high crystal quality of our samples is demonstrated by the excellent agreement between experimental and simulated x-ray-diffraction curves. The transport characteristics of Ga0.38In0.62As/AlyIn1−yAs heterostructures including the evolution of the mobility and of the two-dimensional electron-gas density with temperature and structural parameters are discussed in relation with the relevant scattering mechanisms. The use of a thin spacer layer makes it possible to obtain very high conductivities. Both x-ray and transport measurements show that the strained GaxIn1−xAs layers are pseudomorphic well above the critical thickness calculated with the mechanical equilibrium model. The highest mobilities (13 100 and 103 000 cm2 V−1 s−1 at 300 and 4 K, respectively), obtained with a sheet carrier density of 1.7×1012 cm−2, are measured on a Ga0.38In0.62As/Al0.51In0.49As heterostructure. They are among the best values reported so far for similar structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Carbon incorporation in GaAs and AlxGa1−xAs layers grown by molecular-beam epitaxy (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 77-81 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: GaAs:C and AlxGa1−xAs:C films, grown by solid-source molecular-beam epitaxy with doping levels beyond 1019 cm−3, have been studied by high-resolution double-crystal x-ray diffraction, Hall-effect measurements, and secondary-ion-mass spectroscopy (SIMS). Comparison between x-ray diffraction and Hall-effect data indicate that carbon is preferentially incorporated as acceptor on As lattice sites both in the GaAs:C and in the AlxGa1−xAs:C films. It was found that the higher the AlAs mole fraction the higher is the concentration of carbon incorporated on As sites (CAs). Moreover, SIMS results showed that the total amount of carbon in the host lattices largely exceeds CAs. Our findings are explained by supposing that carbon atoms are incorporated on As sites and on interstitial sites. Furthermore, it is shown that the carbon interstitial concentration can be reduced growing at higher arsenic flux and higher substrate temperature in GaAs:C as well as in AlxGa1−xAs:C layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355200
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Radiative transitions in quaternary In0.52Ga0.18Al0.30As layers grown by molecular beam epitaxy (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 898-904 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The structural and optical properties of molecular beam epitaxy-grown In0.52Ga0.18Al0.30As layers (E300 Kg(approximately-equal-to)1.18 eV), suitable for waveguide applications, have been studied by means of high-resolution x-ray diffraction, absorption, photoluminescence, photoreflectance, and high-excitation intensity photoluminescence spectroscopy. The combination of these techniques allowed us to study the free-exciton states, the impurity related transitions, and the formation of a dense electron-hole plasma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353302
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Structural and vibrational properties of (InAs)m(GaAs)n strained superlattices grown by molecular beam epitaxy (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 786-792 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The structural and vibrational properties of superlattices composed of many periods of highly mismatched InAs and GaAs layers have been studied by means of x-ray diffraction and Raman scattering as a function of the sample geometry. X-ray diffraction measures the average lattice mismatch between the superlattice and the substrate. The long-range order influences the propagative acoustic phonons whereas strain and confinement effects compete in determining the optic vibration frequencies of the InAs layers. The linewidth of the main superlattice peak in the diffraction patterns and the scattering intensities of the acoustic phonons are related to the actual shape of the interfaces. We find that the stability of the structures depends on the total number of periods, in agreement with the predictions of equilibrium elasticity theory. However, the competition between the different relaxation processes is governed by the individual layer thicknesses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347365
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Liquid-phase epitaxy and characterization of Si1−xGex layers on Si substrates (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2158-2163 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Liquid-phase epitaxy allows SiGe alloys of good quality to be grown on Si substrates. We deposit single crystalline, n-type Si1−xGex films with 0.7〈x〈1 from Bi solutions on (111)-oriented Si. The films are up to several μm thick and are uniform in thickness and in composition. The analysis by x-ray diffraction indicates good crystallinity and a dislocation density below 5×107 cm−2. Photoluminescence measurements show well-resolved peaks with the smallest linewidths reported so far for epitaxial SiGe. Hall-effect measurements yield electron concentrations around 1×1016 cm−3 and room-temperature electron mobilities of up to 340 cm2/V s.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346572
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Secondary ion mass spectrometry and x-ray analysis of superconducting Nb/Pd multilayers (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 717-723 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on accurate structural investigations of sputtered Nb/Pd multilayers by means of high-resolution secondary ion mass spectrometry and x-ray reflectivity. The combined use of secondary ion mass spectrometry and x-ray specular reflectivity techniques allows us to study the chemical configuration of the interfaces and to relate it to the observed superconducting properties. Secondary ion mass spectrometry analyses reveal a distinct Nb and Pd modulation and very sharp profiles with abrupt interfaces indicating a negligible interdiffusion of Nb and Pd at the interfaces. Moreover, analyzing the features in the Nb and Pd profiles and correlating them to the oxygen distribution in the multilayers and to the low-angle x-ray patterns, thin layers (3–4 nm thick) of niobium oxide were noticed at the Nb/Pd interfaces, while no oxide layers at the Pd/Nb interfaces could be detected. The role of this oxide layer in the determination of the crossover between three- and two-dimensional superconducting behavior in parallel external magnetic field, is discussed. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371931
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Strain relaxation of Si/Ge multilayers: Coherent islands formation and their evolution as a function of the strain (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 1441-1447 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on a structural study of Si/Ge multilayers grown by molecular-beam epitaxy on (100)-Si substrates. The analyses have been performed by using transmission electron microscopy, high-resolution x-ray diffraction, and secondary-ion-mass spectrometry. The investigated specimens differ in number of periods, period thickness, and in the Si/Ge periods thickness ratio. In particular, we investigate the interdiffusion of the Ge atoms in each superlattice period of the epilayer and in the epilayer as whole. The interdiffusion causes a broadening of the nominal thickness of the Ge layer producing a SixGe1−x alloy. Furthermore, the Ge content in the multilayer periods increases as a function of the growth time, i.e., the superlattice periods close to the sample surface contain more Ge atoms if compared to the periods close to the substrate/superlattice interface. We find two steps in the strain relaxation: (i) In each period the strain energy density is partially reduced by the formation of coherent islands; (ii) at a certain value of the strain energy density the shape of the islands changes and the structures relax partially or completely the accumulated strain energy by nucleation of extended defects. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360982
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Structural characterization of lattice matched AlxIn1−xAs/InP and GayIn1−yAs/InP heterostructures by transmission electron microscopy and high-resolution x-ray diffraction (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 2403-2410 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this work we report on transmission electron microscopy and high-resolution x-ray diffractometry studies of lattice matched AlxIn1−xAs/InP and GayIn1−yAs/InP epilayers grown by molecular beam epitaxy on InP(100) substrates. High-resolution and diffraction contrast electron microscopy measurements show the presence of different contrast zones in the epilayers. The analysis of high-resolution x-ray diffraction measurements and computer simulations ascribe these zones to the presence of a compositional gradient in the epilayers. A comparison among investigated samples grown under slightly different growth conditions combined with an analysis of the crystal defects is presented. Growth-induced small variations in the chemical composition of the epilayer can produce differences in the structural quality of the epitaxial layer. Finally, a few monolayers thick and highly strained film of InAsP, is observed in all investigated samples at the substrate/epilayer interface. The formation of this interface layer is explained by the exchange of As and P during exposure of the InP surface to As4 before the growth. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360162
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Structural analysis of ZnS/GaAs heterostructures grown by hydrogen transport vapor-phase epitaxy (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2429-2434 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The structural characterization of ZnS epilayers grown by hydrogen transport vapor-phase epitaxy on (100)-oriented GaAs substrates is reported. X-ray-diffraction measurements in both double-axis (DA) and single-axis modes were performed to determine the residual strain tensor and the strain temperature dependence of the epilayer in the range between 25 and 650 °C. From the analysis of the data obtained by DA measurements of several symmetric Bragg reflections at different azimuth angles and several asymmetric reflections recorded in different geometries, an orthorhombic distortion of the ZnS lattice was found. The crystallographic symmetry could be explained by an asymmetric distribution of the misfit dislocation density in the interface plane along the [011] and [01¯1] directions. The temperature dependence measurements of the strain tensor components between room temperature and the growth temperature (650 °C) allowed determination of the thermal misfit between ZnS and GaAs and the linear thermal-expansion coefficient of ZnS. Finally, triple-crystal diffractometry and secondary-ion-mass spectrometry were used to investigate the chemical nature of the ZnS-GaAs interface. The results indicate the presence of an interdiffused ZnS-GaAs interface region, whose occurrence turns out to be associated with the initial defect structure of the substrate surface before the growth. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358769
    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...