Polarization control of self-assembled quantum-dot surface-emitting lasers

The operation of QD lasers at room temperature has become possible by using selfassembled quantum dots (QDs), thus improving the capabilities of these lasers. We fabricated QD vertical-cavity surface-emitting lasers (VCSELs) with these self-assembled QDs. Room temperature lasing was achieved by stacking 10-period dot layers in the active region. The anisotropy of a QD structure can be used to improve device performance. Using this anisotropy, we have achieved polarization control in VCSELs. The self-assembled InGaAs QDs are grown on a (100) substrate at 520°C by molecular beam epitaxy. A plan-view high-resolution scanning electron microscopic (HR-SEM) image and atomic force microscopic (AFM) image show the dot shape. Photoluminescence (PL) spectra at room temperature is given