Localization Properties of Trions

Abstract

78.55.Cr Dedicated to Professor Dr. Roland Zimmermann on the occasion of his 60th birthdayWe present an experimental and theoretical microscopic view on the optical trion spectrum in the presence of disorder. Although strong spatial fluctuations in near-field spectra point to strongly localized trion states, the far-field spectrum reveals the contribution of weakly localized trion states in addition. It is shown, that the underlying physics involves the optical transition between two disorder eigenstates of different localization length.

Determination of Trion and Exciton Lineshapes in Modulation-Doped Quantum Wells

“…2, we see that it is impossible to reproduce both low energy and high energy tail of exciton and trion resonance because of their strong asymmetry. We note that in the measured spectra, the low-energy tail of the trion resonance predicted by 25 is marginal and can be fairly well reproduced by our fit. Conversely, a high energy tail of exciton and trion resonances develops as the electron density increases.…”

“…As for the oscillator strength, not much can be said, since we did not include any dependence on the electron density in our model. We did so intentionally because current theoretical models conclude that the trion oscillator strength depends on the volume of the sample 25 . We think that it is a failure of the three-particle oversimplified trion model which is, strictly speaking, only correct in quantum dots.…”

Coherent dynamics of localized excitons and trions in ZnO/(Zn,Mg)O quantum wells studied by photon echoes

“…Since both the exciton and trion binding energies are clearly larger than the localization energy, the internal motion inside of exciton and trion are not strongly modified and the localization affects only the center-of-mass wave function. Respective model calculations were carried out so far only for the one-dimensional case of trions in a quantum wire 18 . For excitons localized in a QW, only a weak decrease of the oscillator strength is found for increasing localization 19 , that is much less dramatic than the T 1 change seen in Fig.…”

Optical Detection of Electron-Depletion Region Surrounding Metal Electrode on a Dilute Two-Dimensional Electron Gas

“…Negatively charged excitons and/or 2DEG recombination emission dominate the PL in the presence of a 2DEG, whereas neutral excitons appear as the 2DEG density approaches zero. Although near-field microscopy is necessary to study strongly localized or confined electrons, [5][6][7] far-field micro-PL is also available to image the distribution of electrons with spatial resolution of the order of 1 µm.…”

“…Recent experimental works have demonstrated a technique for imaging the distribution of electrons by scanning optical microscopy. [5][6][7] The point of these experiments is that the photoluminescence (PL) spectra show distinct peak structures depending on the background 2DEG density. Negatively charged excitons and/or 2DEG recombination emission dominate the PL in the presence of a 2DEG, whereas neutral excitons appear as the 2DEG density approaches zero.…”