Magneto-optical study on exciton screening in p-type AlxGa1-xAs/InyGa1-yAs quantum wells
1997 (English)In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 56, no 8, 4853-4862 p.Article in journal (Refereed) Published
We have studied exciton unbinding in empty and p-doped quantum wells, using magnetophotoluminescence excitation measurements. The use of p-type quantum wells allows us to discriminate unambiguously between exciton bleaching by Coulomb screening and by the Pauli exclusion principle. We found that the ground-state heavy-hole exciton, which experiences both effects, is unbound at hole densities in the range (6-9) x 10(15) m(-2). In contrast, the ground-state light-hole and first excited heavy-hole excitons, which are only screened by the Coulomb interaction, still have a finite binding energy at these densities. However, for both bands, its Value is far below what is found in an undoped well. Furthermore, we found a strong indication that, in p-doped wells, the excitons of excited subbands are less efficiently screened than those of the Light-hole ground state, due to the lesser overlap of the screening ground-state heavy holes with the excited subbands than with the ground-state light holes.
Place, publisher, year, edition, pages
American Physical Society , 1997. Vol. 56, no 8, 4853-4862 p.
IdentifiersURN: urn:nbn:se:liu:diva-116066DOI: 10.1103/PhysRevB.56.4853ISI: A1997XV00700086OAI: oai:DiVA.org:liu-116066DiVA: diva2:813298