M. Dworzak

Recombination dynamics of localized excitons in InGaN quantum dots

Indium-rich fluctuations in ultrathin InGaN layers act at low temperatures as a dense ensemble of quantum dots (QD). This leads to a complex potential landscape with localization sites of widely varying depth for excitons. We report on investigations of the recombination mechanisms of excitons localized in InGaN∕GaN QD structures by time-resolved and spatially resolved photoluminescence (PL) measurements. The structures were grown by metal-organic chemical-vapor deposition on Si (111) substrates. Sharp lines originating from single QDs could be observed. Their PL decays show monoexponential behavior. Similar transition energies have different time constants. Thus, the well-known nonexponential PL decay of the QD ensemble is assigned to the summation of monoexponential decays originating from individual QDs with different exciton lifetimes.

Lateral redistribution of excitons in CdSe'ZnSe quantum dots

Lateral redistribution processes of excitons localized in CdSe/ZnSe quantum dot structures are investigated by time-integrated and time-resolved spectroscopy. The photoluminescence properties are governed by lateral energy transfer within a dense ensemble of quantum dots. The quantum dots differ in size and Cd concentration and provide a complex potential landscape with localization sites for excitons. At low temperatures, lateral transfer by tunneling leads to a redshift with increasing delay after pulsed excitation. The mobility edge was determined to 2.561 eV. Above 100 K, thermally activated escape and recapture of excitons cause a strong redshift of the PL maximum in the first 500 ps.

Magneto-optical properties of bound excitons in ZnO

We present results of magneto-optical measurements and theoretical analysis of shallow bound exciton complexes in bulk ZnO. Polarization and angular dependencies of magnetophotoluminescence spectra at 5 T suggest that the upper valence band has

Reconciliation of luminescence and Hall measurements on the ternary semiconductor CuGaSe2

{\ensuremath{\Gamma}}_{7}

Influence of structural nonuniformity and nonradiative processes on the luminescence efficiency of InGaAsN quantum wells

symmetry. Nitrogen doping leads to the formation of an acceptor center that compensates shallow donors. This is confirmed by the observation of excitons bound to ionized donors in nitrogen doped ZnO. The strongest transition in the ZnO:N

Origin of the Broad Lifetime Distribution of Localized Excitons in InGaN/GaN Quantum Dots

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Dephasing and energy relaxation processes in self‐assembled In(Ga)As/GaAs quantum dots

transition) is associated with a donor bound exciton. This conclusion is based on its thermalization behavior in temperature-dependent magnetotransmission measurements and is supported by comparison of the thermalization properties of the

Luminescence Efficiency of InGaN/GaN Quantum Wells on Bulk GaN Substrate

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Redistribution of localised excitons in CdSe/ZnSe quantum dot structures

and

On the Origin of the Unexpected Annealing Behavior of GaInNAs Quantum Wells

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