Spin relaxation in n-doped GaAs/AlGaAs quantum wells

Summary form only given. An important requirement for a future spin-electronics in semiconductors, called spintronics, is the profound knowledge of the spin relaxation of electrons in semiconductors. Therefore, we investigate the spin-relaxation of electrons in modulation and homogeneously n-doped quantum wells. The spin-relaxation is measured in dependence of excitation density and temperature at different excitation energies. The measurement techniques are time-resolved Faraday rotation and time-resolved photoluminescence. The temperature dependent measurements exhibit an increase of the relaxation time from low temperatures up to 60 K. At higher temperatures, the spin relaxation time decreases again with temperature which we attribute to the Dyakonov-Perel mechanism. At temperatures up to 150 K, the spin relaxation time of the modulation doped sample is much higher than in the homogeneously doped sample. The difference of the two spin relaxation times decreases with increasing temperature. Above temperatures of 220 K, the spin relaxation times become equal.