Thermal Carrier Escape and Capture in CdTe Quantum Dots

• Published in: Physica status solidi. B. Basic research Vol. 224; no. 2; pp. 465 - 469
• Main Authors: Maćkowski, S., Kyrychenko, F., Karczewski, G., Kossut, J., Heiss, W., Prechtl, G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin WILEY-VCH Verlag Berlin GmbH 01.03.2001; WILEY‐VCH Verlag Berlin GmbH; Wiley
• Subjects: 71.35.Cc; 78.47.+p; 78.55.Et; 78.67.Hc; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Quantum dots; S8.13; Temperature dependence; Inorganic compounds; Semiconductor materials; Charge carriers; Quantum dots; Zinc tellurides; Transition element compounds; Photoluminescence; Line widths; Binary compounds; Experimental study; Time resolved spectra; Spectral shift; Excitons; Cadmium tellurides; Distribution functions
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/1521-3951(200103)224:2<465::AID-PSSB465>3.0.CO;2-F

We studied optical properties of CdTe quantum dots (QDs) by steady‐state and time‐resolved photoluminescence spectroscopy. By changing the excitation power at high temperatures (about T = 70 K) we can significantly influence the distribution of excitons within the quantum dot ensemble. The effect manifests itself by a large (100 meV) red shift of the PL emission energy when the excitation power decreases by five orders of magnitude. This red shift is accompanied by a decrease of the linewidth of the emission band. We discuss these effects in the frame of a model of thermally induced redistribution of carriers between the zero‐dimensional electronic states within the quantum dot ensemble. Moreover, we found that the exciton decay time of the QD emission increases dramatically when the number of excitons injected into the system is reduced.