Room temperature observation of optical modes in transferred rolled-up InGaAs/GaAs quantum dot microtube with AlGaAs confining layers

Materials Science in Semiconductor Processing. 2018. Vol. 79. No. 6. P. 20–23.

Mao G., Wang Q., Chai Z., Cao J., Liu H., Ren X., Maleev N., Vasil’ev A., Zhukov A., Ustinov V.

We realized the excellent confinement of carriers in single-layer InAs quantum dots (QDs) via introducing two
AlGaAs confining layers (CLs), and then fabricated the corresponding rolled-up InGaAs/GaAs QD microtubes by
conventional photolithography and wet-etching. Subsequently, the as-fabricated AlGaAs confined QD microtubes
were transferred to a Si-based SiOx substrate using a simple liquid-assisted substrate-on-substrate transfer
process, thus obtaining the microtube ring resonators. Through micro-photoluminescence (μPL) measurement,
optical modes were observed at room temperature and a maximum Q-factor of ~ 550 was demonstrated. In
order to clearly show the effect of AlGaAs CLs, we also fabricated and transferred QD microtubes without AlGaAs
CLs for comparison. μPL spectra collected at 80 K confirmed that the PL intensity of the central optical mode was
increased ~ 10 times with the assistance of AlGaAs CLs. We have confidence that QD microtube ring resonators
can be further improved through the incorporation of double-layer QDs together with AlGaAs CLs.

Keywords: наноструктуры, nanostructures