Strain Reduction and Long Wavelength Emission from InAs/GaAs Quamtum Dots by Using Growth Interruption in Molecular Beam Epitaxy

Abstract

We obtained light emission with a wavelength of 1242 nm at room temperature from self-assembled InAs quantum dots grown by molecular beam epitaxy (MBE) with interruption and embedded in the GaAs layer. Further, when a 6 nm InGaAs strain reducing layer was added the emission wavelength was around 1330 nm. The full width at half maximum is as narrow as 28.3 meV. InAs quantum dots with less size fluctuations were obtained on GaAs(100) substrate by using the growth interruption of 15 s for every 0.11 monolayer (ML) after depositing 1.9 ML of InAs continuously. Atomic force microscopy images show that the initial continuous growth up to 1.9 ML acted as a “seed” and helped to double the dot density. The subsequent supply of In with interruptions resulted in a large dot size while maintaining a high dot density. The six layer stacked (d=22 nm) quantum dots (QDs) grown with interruptions showed nearly 7 times stronger photoluminescence at room temperature than the continuously grown structure.