Effect of GaAs multi-atomic steps thickness on the structural and optical properties of self-assembled In0.5Ga0.5As quantum dots

Abstract

Self-assembled In0.5Ga0.5As quantum dots (QDs) were grown on various thickness of GaAs multi-atomic steps layer using Stranski-Kratanov (SK) growth mode. Atomic force microscopy (AFM) analysis indicates fluctuation of size and density of the dots. The varieties of dots formed on the surface are believed to be the affect of different structure of GaAs multi-atomic steps with different thicknesses. The high-density small dots are formed at 200 nm thick GaAs multi-atomic steps. The PL measurement shows evolution of peak shape as an effect of different surface morphology of the samples as a result of increasing thickness of GaAs multi-atomic steps layer. This study shows the formations of the dots grown by Stranski-Krastanov growth mode not only influenced by growth parameters but also strongly dependent on structures of GaAs multi-atomic steps layer. The modification of size, shape, uniformity, and density of QDs are essential for device applications especially for QD lasers.