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Last name: GUILLET
First name: Thierry
International audience
Time-integrated photoluminescence experiments are used to study the excitonic optical recombinations in wurtzite ZnO∕Zn1−xMgxO single quantum wells of varying widths and magnesium compositions. By comparing experimental results with a variational calculation of excitonic energies, the authors determine the magnitude of the built-in electric...
We investigate by time-resolved spectroscopy the consequences of large internal electric fields on the exciton recombination dynamics in ZnO/(Zn,Mg)O quantum wells.
We report on the optical spectroscopy of a series of ZnO/(Zn, Mg)O quantum wells of different widths, using time-resolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The barriers consist of Zn0.78Mg0.22O layers. The presence of large internal electric fields...
We report on polarization-resolved micro-photoluminescence experiments performed on a single GaN/AlN polar quantum dot (QD) grown on Si(111) substrate. We have performed a systematic study of about 50 QDs. The emission of about half of the QD excitons is strongly linearly polarized, up to 90%. Such a polarization is known to be the...
International audience
We present single dot spectroscopy of hexagonal GaN/AlN self‐assembled quantum dots (QDs) grown by MBE along the (0001) axis. The GaN quantum dots are grown on an AlN epilayer on Si (111) substrate, with dot densities between 108 and 1011 cm−2. We study the micro‐photoluminescence spectra of a few quantum dots. In the energy range corresponding...
Wurtzitic ZnO∕(Zn,Mg)O quantum wells grown along the (0001) direction permit unprecedented tunability of the short-range spin exchange interaction. In the context of large exciton binding energies and electron-hole exchange interaction in ZnO, this tunability results from the competition between quantum confinement and giant quantum confined...
We have investigated a series of samples embedding ZnO/(Zn,Mg)O quantum wells of different sizes, in wurtzite phase, by using timeresolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The presence of large internal electric fields in these quantum wells...
Time-resolved photuminescence spectroscopy investigations of nonpolar homoepitaxial ZnO/(Zn,Mg)O quantum wells.
We report microphotoluminescence studies of single GaN/AlN quantum dots grown along the (0001) crystal axis by molecular-beam epitaxy on Si(111) substrates. The emission lines exhibit a linear polarization along the growth plane but with varying magnitudes of the polarization degree and with principal polarization axes that do not necessarily...
We report microphotoluminescence studies of single GaN∕AlN quantum dots grown by molecular beam epitaxy on Si(111) substrates. Small groups of emission lines characterize each single dot, with linewidths mostly limited by our experimental setup to 1 or 2meV. By using time-dependent microphotoluminescence, we observe both the continuous and...
International audience
National audience
Self-assembled semiconductors QDs are of great interest in fundamental physics as well as inapplied physics. In GaN/AlN heterostructures, the huge band-offset and the strong excitonicbinding lead to an important exciton confinement allowing an emission even at roomtemperature. GaN QDs grown along the (1000) axis are named "polar" due to their...
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Optical investigation of non polar ZnO/(Zn,Mg)O quantum wells
Optical investigations of non-polar homo-epitaxial ZnO/(Zn,Mg)O quantum wells
We report growth of high quality ZnO/Zn0.8Mg0.2O quantum well on M-plane oriented ZnO substrates. The optical properties of these quantum wells are studied by using reflectance spectroscopy. The optical spectra reveal strong in-plane optical anisotropies, as predicted by group theory, and marked reflectance structures, as an evidence of good...
Phonon-assisted exciton formation in ZnO/(Zn, Mg)O single quantum wells grown on C-plane oriented substrates.
International audience
Individual pillars were etched from a sample embedding a single plane of GaN/AlN quantum dots, deposited by molecular beam epitaxy on a sapphire substrate. Pillars with diameters ranging from 0.1 to 5 μm were fabricated by electron-beam lithography and SiCl4 reactive ion etching. The PL from a single pillar could be measured by using a confocal...
International audience
Properties of self-assembled quantum dots (QDs), often referred to as artificial atoms in solid state, are very interesting in order to study physical effects specific to single quantum systems such as the single-photon emission. Thanks to their huge vertical quantum confinement, GaN QDs are emitting even at room temperature and on a large UV...
Properties of self-assembled quantum dots (QDs), often referred to as artificial atoms in solid state, are very interesting in order to study physical effects specific to single quantum systems such as the single-photon emission. Thanks to their huge vertical quantum confinement, GaN QDs are emitting even at room temperature and on a large UV...