Carrier Lifetime and Electron Spin Relaxation Time in (110)-Oriented GaAs–AlGaAs Quantum-Well Micro-Posts

Carrier lifetime and electron spin relaxation time in (110)-oriented GaAs-AlGaAs quantum-well (QW) micro-posts are investigated by polarization- and time-resolved photoluminescence measurements. The long electron spin relaxation time in QWs on GaAs (110) is found to be preserved even when the sidewall boundaries with fast surface recombination are introduced and the carrier lifetime is drastically shortened. Rate equation analysis shows that spin-controlled vertical-cavity surface-emitting lasers with such (110)-QW micro-posts will exhibit faster switching of lasing circular polarizations than that we previously demonstrated. In particular, 20-GHz switching is expected with 0.5-μm posts.