A variational calculation of the ground state energy of a biexciton in a
GaAs/AlGaAs quantum well is presented. The well width fluctuations leading to
trapping of the biexcitons are modeled by a parabolic potential. The results
obtained for different well widths are compared with recent experimental data.
Good agreement is obtained both for the biexciton binding energy and for the
Haynes factor. We find that the structure of a biexciton is similar to the one
of the H_2 molecule.Comment: 9 pages, 4 figure

Certier, M.

Germain, M.

Heuken, M.

Kartheuser, E.

Pages, O.

Soltani, M.

Taudt, W.

English

arXiv

Due to their extended electronic structure shallow donors are believed to be very sensitive to confinement effects. Our interest is to investigate the influence of size on the properties of shallow donor phosphorus in mechanically milled silicon microcrystals. The crystallinity of powders is confirmed by X‐ray diffraction and the size as determined by scanning electron microscopy was found to be 0.25 μm for smallest to 4 μm for largest microcrystals. In the current experiment we use electron paramagnetic resonance to measure the hyperfine interaction between donor electron and P nucleus. The hyperfine constant and mutual overlap of donor wave functions exhibit significant dependence on grain size and subsequent annealing. By photoluminescence spectroscopy the appearance of a strong band around 1515 nm which shifts to higher energies with diminishing grain size has been established

Pawlak, B.J.

Gregorkiewicz, T.

Ammerlaan, C.A.J.

NARCIS 

Confinement Effects of Phosphorus Donors Embedded in Silicon Microcrystals

Publikationsserver der RWTH Aachen University

Photoluminescence of nitrogen-doped ZnSe layers

We present time-, temperature- and intensity-dependent photoluminescence measurements of undoped, n-type and p-type GaN epilayers. In the nominally undoped samples we observe at low temperatures the trapping of free excitons by neutral donors and subsequent radiative recombination. In the n-type Si-doped samples bound-exciton luminescence is dominant over a wide range of temperatures. The luminescence from p-type Mg-doped samples is dominated by shallow-donor-shallow-acceptor pair recombination and by a deep blue centres at 3.0 eV. These two emission bands show identical temperature and linear intensity dependence

Hess, S

Taylor, RA

Ryan, JF

Cain, NJ

Roberts, V

Roberts, J

Oxford University Research Archive (ORA)

physica status solidi (b)

Photoluminescence studies of Mg-doped and Si-doped gallium nitride epilayers

Taylor, Robert

Ryan, John

ORA - Oxford University Research Archive

Electronic Raman scattering was used to investigate excited states of shallow acceptors in Zn- and in Cd-doped p-type InP with acceptor concentrations in the range between 1016 cm−3 and 1018 cm−3. Well resolved transition lines were obtained for acceptor concentrations of about 1017 cm−3 (Zn-doped) and 5 × 1017 cm−3 (Cd-doped), at higher concentrations the levels merge into broad bands. A linear correlation between the normalized intensity of the electronic spectrum and the acceptor concentration was found. The measured acceptor energy levels were used to prove which sets of published Luttinger parameters γ1, γ2 and γ3 are compatible with our results

Binding energy of localized biexcitons in quantum wells

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Publikationsserver der RWTH Aachen University

Oxford University Research Archive (ORA)

ORA - Oxford University Research Archive

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Archivio della ricerca- Università di Roma La Sapienza

Oxford University Research Archive