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HL: Halbleiterphysik

HL 28: Optische Eigenschaften

HL 28.4: Vortrag

Mittwoch, 10. März 2004, 16:00–16:15, H17

Excitons and Plasma: Two Sources for Excitonic Photoluminescence: — •Sangam Chatterjee^1,2, Sorin Mosor², Claudia Ell², Galina Khitrova², Hyatt M. Gibbs², Walter Hoyer¹, Mackillo Kira¹, Stephan W. Koch¹, John P. Prineas³ und Heinrich Stolz⁴ — ¹Fachbereich Physik und Wissenschaftliches Zentrum für Materialwissenschaften, Philipps-Universität Marburg, Renthof 5, 35032 Marburg. — ²The University of Arizona, Optical Sciences Center, 1630 E. University Blvd, Tucson, AZ 85721, USA. — ³University of Iowa, Iowa City, IA 52242, USA. — ⁴Fachbereich Physik, Universität Rostock, D-18051 Rostock

Photoluminescence from InGaAs quantum well structures exhibits a strong peak at the energetic position of the 1s exciton resonance. This is independent of the presence of an incoherent excitonic population. We perform time-resolved photoluminescence experiments over a large range of carrier density and lattice temperatures. A detailed analyses using a microscopic theory identifies the plasma and excitonic contributions to the emission. A phase diagram for the bright incoherent excitonic contributions is then extracted. At low lattice temperatures, 4K, and intermediate and low densities small fractions of bright excitons can completely dominate the emission. For larger lattice temperatures, 50K, the excitonic contributions is negligibly small.