Nanosecond recombination lifetimes and spin relaxation times in (110) InGaAs/AlGaAs quantum wells at room temperature

Abstract

Quantum wells in InGaAs/AlGaAs with (110) orientation are attractive as active layers in spin-controlled lasers with circularly polarized emission, while the spin relaxation time is expected to be larger than for (100)-oriented layers. However, the hitherto reported recombination lifetimes (40 ps) and spin relaxation times (440 ps) of (110) InGaAs/AlGaAs structures are insufficient. Here it is shown that higher growth temperatures and higher V/III beam equivalent pressure ratios than previously used in crystal growth by molecular beam epitaxy lead to recombination and spin relaxation times in the nanosecond range at RT, meeting the requirements for application in spin lasers.