Stacking of over 150 layers of InAs quantum dots on InP(311)B substrates

We fabricated stacks of InAs quantum dots (QDs) on InP(311)B substrates using a novel strain-controlled technique, and improved their size uniformity by precisely controlling the composition of the strain-compensating spacer layers. Consequently, we achieved a 150-layer stack of InAs QDs in which the density of the QDs exceeded 5 × 10¹²/cm² which cannot be obtained using conventional techniques for fabricating QDs. In a sample of a 150-layer stack, the QDs showed good size uniformity and an ordered structure. In addition, a strong 1.5 μm photoluminescence emission was observed in this sample at room temperature, which indicates that it would be suitable for fiber-optic communication systems.