Publikationen


Suche nach „[R.] [Roberts]“ hat 4 Publikationen gefunden
Suchergebnis als PDF
    Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen

    Zeitschriftenartikel

    P. Harrison, W. Hagston, T. Piorek, Thomas Stirner, J. Fatah, R. Roberts, D. Ortega, A. Chesworth

    Monte Carlo simulations of carrier transport and relaxation in superlattices

    Superlattices and Microstructures, vol. 15, no. 2, pp. 209-213

    1994

    DOI: 10.1006/spmi.1994.1042

    Abstract anzeigen

    Monte Carlo simulations of carrier transport through an undoped superlattice into an extended well are described. The results illustrate clearly the important role played by LO phonons in relaxing the energy and the desirability of designing structures which minimize the need for acoustic phonon participation. Attention is drawn to the fact that although, for the standard structures investigated, the LO phonon relaxation rate is relatively independent of the miniband and/or the quantum well eigenstates, the precise shape of the form-factor for an allowed LO transition could play an important role in deciding the relative number of 'slow' carriers in an actual system.

    Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen

    Zeitschriftenartikel

    P. Harrison, W. Hagston, T. Piorek, Thomas Stirner, J. Fatah, R. Roberts

    Effects of interfaces and interface roughness in diluted magnetic semiconductor microstructures

    Superlattices and Microstructures, vol. 16, no. 1, pp. 11-15

    1994

    DOI: 10.1006/spmi.1994.1100

    Abstract anzeigen

    In this work a numerical model of anti-ferromagnetic spin-pairing in diluted magnetic semiconductors is used to determine the paramagnetic behaviour of both abrupt and rough interfaces. A detailed study of the paramagnetic behaviour of the individual monolayers adjacent to an abrupt interface with a non-magnetic material has not only predicted quantitatively the enhanced paramagnetism in the ultimate monolayer, it has also predicted a depressed paramagnetism in the penultimate monolayer. Furthermore, the results of the theoretical model have been compared with experimental observations in order to gain insight into intrinsic and structural properties of heterojunctions in diluted magnetic semiconductors.

    Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen

    Vortrag

    R. Roberts, P. Harrison, W. Hagston, Thomas Stirner

    Stark ladders in strongly coupled finite superlattices

    Posterpräsentation

    3rd International Conference on Optics of Excitons in Confined Systems, Montpellier, Frankreich

    1993

    Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen

    Zeitschriftenartikel

    R. Roberts, P. Harrison, W. Hagston, Thomas Stirner

    Stark ladders in strongly coupled finite superlattices

    Journal de Physique IV, vol. 3, no. C5, pp. 203-206

    1993

    Abstract anzeigen

    It is shown that the nature and extent of wavefunction localisation of miniband states in an external electric field can be markedly different for finite superlattice structures, compared with infinite and is dependent on the strength of interaction between the initial electron (and hole) miniband states. The question of blue shifts and excitonic effects is described and possible device applications for strongly interacting superlattices structures are discussed.