Impacts of Crystal Quality on Carrier Recombination and Spin Dynamics in (110)-Oriented GaAs/AlGaAs Multiple Quantum Wells at Room Temperature

Abstract

We have systematically investigated the structural properties, carrier lifetimes, namely, photoluminescence (PL) lifetimes (τPL), and electron spin relaxation times (τs) in (110) GaAs/AlGaAs multiple quantum wells (MQWs) by using time-resolved PL measurements. The MQWs were grown by molecular beam epitaxy within a wide range of the growth temperature Tg (430–600 °C) and a high V/III flux ratio using As2. At 530 °C < Tg < 580 °C, we found that the quality of the heterointerfaces is significantly improved, resulting in τPL~40 ns at RT, one order of magnitude longer than those reported so far. Long τs (~6 ns) is also observed at RT.

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

“…17) In terms of τ r , an indicator of crystal quality, high-quality (110) GaAs/AlGaAs QWs with τ r in the nanosecond range have been demonstrated using optimized growth conditions for homoepitaxial growth on (110) GaAs substrates. [18][19][20][21][22] InGaAs, a ternary semiconductor, is more attractive than GaAs for the active well layer due to its tunable wavelength in the desired range, improved differential gain and reduced threshold current resulting from the reduced density of states. 23) However, there are few reports on τ r and τ s for (110) InGaAs QWs.…”