Time-resolved investigations of excitonic recombination in highly strained InAs/Al0.48In0.52As quantum wells

Abstract

We have investigated the exciton dynamics in strained InAs/Al 0.48In0.52As quantum wells with well thicknesses of 2, 4, and 5 monolayers by time-resolved photoluminescence spectroscopy. Temperature-dependent measurements of the decay time reveal a significant drop of the decay time above a critical temperature which depends on the well width. The simultaneous measurement of the decay time and the integrated photoluminescence intensity enables us to estimate the radiative time constant. As can be shown from the temperature dependence of the decay time nonradiative processes become more and more important at higher temperatures. The strong increase of the radiative lifetime at higher temperatures is attributed to a thermal ionization of the excitons.