Recent progress on crystal growth of high-quality (110)GaAs-based quantum wells for spin laser

Abstract

(110)-oriented GaAs-based quantum wells (QWs) are promising active layers of spin lasers because of long spin relaxation time at room temperature. So far, (110)GaAs/AlGaAs QWs have been investigated intensively and long carrier lifetime of several ns has been reported. In contrast, there have been few reports on the crystal growth of (110)InGaAs/(Al)GaAs QWs despite its great potential to the active layer, resulting in rather poor crystal quality with short carrier lifetime. In this study, we tried to grow high-quality (110)InGaAs/(Al)GaAs QWs by optimizing MBE growth conditions and obtained long carrier and spin lifetime (>1 ns) in the QWs grown with relatively high temperature and As/Ga flux ratio. This reveals that the (110)InGaAs/(Al)GaAs QWs are applicable to the active layer of spin lasers. In addition, we propose a novel structure for a spin transport layer between the ferromagnetic electrode (spin injector) and the active layer of spin laser.