Time-resolved photoluminescence of diluted magnetic semiconductor quantum wells

Abstract

The authors are examining magnetic effects on the photoluminescence from a variety of Cd1-x Mnx Te- Cd1-y Mny Te quantum well structures and superlattices. A streak camera system with 35-ps resolution is used to gather time-resolved spectra, and these are complemented by DC energy-resolved spectra that show the integrated time response. The luminescence is found to be highly polarized in modest magnetic fields at low temperatures. This effect is though to arise from the formation of bound magnetic polarons. The authors are studying the effect of dimensionality on polaron formation by systematically thinning the CdMnTe barriers of nonmagnetic quantum well superlattices into the dimensional crossover regime. The luminescence decay rates decrease with decreasing magnetic field and decreasing confinement, reaching 500 ps in 8.6-nm wells.