Exciton spin relaxation in ln_(0.53)Ga_(0.47)As/AIAs_(0.56)Sb_(0.44) quantum wells

摘要

The spin relaxation process of In_(0.53)Ga_(0.47)As/AlAs_(0.56)Sb_(0.44) quantum wells is investigated by spin-dependent pump and probe reflectance measurements with a high time resolution of 200 fs. The observed spin relaxation time of 17.5 ps at 20 K indicates high potential for applications to high-speed optical devices. A positive temperature dependence of the spin relaxation time due to the unique band structure is observed at 30-100 K. The spin relaxation is found to be mainly governed by the Bir-Aronov-Pikus process [Sov. Phys. JETP 42, 705 (1976)] below 100K and by the D'yakonov-Perel' process above 100 K.