[9a-PA7-1~9] 13.6 Nanostructures, quantum phenomena, and nano quantum devices

English Presentation

[9a-PA7-2] Optical spin injection and detection in low-density InAs/GaAs QD bilayers

〇Ronel Intal Roca¹, Rhenish Simon¹, Itaru Kamiya¹ (1.Toyota Tech. Inst.)

Keywords:

quantum dots,MBE,optical spin injection

Recently, molecular beam epitaxy (MBE) -grown self-assembled InAs/GaAs quantum dots (QDs) are becoming promising candidates for quantum information applications. Particularly, for this application, a low areal density, on the order of 10⁸ cm^-2, is ideal. Therefore, maintaining reliable and precise QD density control is crucial. It has recently been reported that such densities can be achieved using stack submonolayer (SML) growth. However, it was also reported that reducing the QD density to such low densities has the side-effect of leading to smaller QDs that emit at shorter wavelengths. One way to overcome this issue that has been proposed to control the emission wavelength independently to the QD density is the use of QD bilayers, where the first layer of QDs is used to control the density, while the second layer of QDs is used to tune the emission wavelength. Whereas this approach has shown promise at independent tuning of the emission wavelength, the spin dynamics in this type of low-density QD bilayers are unknown. The present work aims to study the spin dynamics in low-density QD bilayers using circularly-polarized photoluminescence (CP-PL) measurements.