Electron- and hole-spin relaxation within excitons in GaAs quantum wells by non-degenerate pump-and-probe measurements

Abstract

We report on an experimental investigation of electron-, hole-, and exciton-spin relaxation times in intrinsic GaAs quantum wells. We present non-degenerate pump-and-probe measurements followed by a detailed analysis of the differential transmission spectra in order to identify different spin relaxation channels. Dynamics of spin relaxation is generally considered to be multiexponential and therefore a dynamical model taking into account four exciton states is used in order to determine the various relaxation times. In contrast to other experimental work, we also consider transitions to different biexciton states. This allows us to identify spin relaxation processes of electrons, holes, and excitons and to assign them fitted time constants.