https://doi.org/10.1140/epjb/e2006-00444-x
Lateral carrier tunnelling in stacked In(Ga)As/GaAs quantum rings
1
Unité de Recherche Des Physiques des Semiconducteurs et Capteurs, Institut Préparatoire aux Études Scientifiques et Techniques, La Marsa 2070, Tunis, Tunisia
2
Instituto de Ciencia de los Materials, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
3
Instituto de Microelectrónica de Madrid, Isaac Newton 8, 28760 Tres Cantos, Madrid, Spain
Corresponding author: a ouerghuiwalid@yahoo.fr
Received:
21
June
2006
Revised:
6
November
2006
Published online:
22
December
2006
Exciton recombination dynamics in vertical stacks of InGaAs quantum rings have been studied by means of continuous wave and time resolved photoluminescence under low excitation density conditions. We have paid special attention to the effect of the carrier coupling on the exciton radiative lifetime: weak (14 nm spacer sample), intermediate (4.5 nm spacer sample), where the size filtering effects (towards small rings) compensate partially that arising from carrier coupling (towards lower energies), and strong electron and hole coupling (1.5 nm spacer sample) between layers. Experimental decay times in the latter two cases have been compared to the times simulated with a multi-quantum well based model, which accounts for the observed change of carrier coupling regime. The most important effect is observed when the hole wave function overlap along the growth direction becomes important (1.5 nm spacer sample). This situation makes important the lateral tunneling of excitons between rings, given their large lateral size, which is characterized by times around 5 ns at the emission peak energy (rings with the most probable size of the distribution).
PACS: 71.55.Eq – III-V semiconductors / 73.43.Jn – Tunneling / 73.21.Ac – Multilayers / 71.35.-y – Excitons and related phenomena
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006