Surface morphology and lateral distribution of self-assembled in0.5Ga0.5AS nanostructures grown on gaAs (100) substrate

Abstract

This paper investigates the size, density and uniformity of double layer In0.5Ga0.5As nanostructures as a function of GaAs buffer layer thickness. Observation of surface morphology by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) shows that the dots formation depends strongly on the GaAs buffer layer thickness. The size of dots reduce with the increase in the buffer layer thickness. Selfassembled In0.5Ga0.5As nanostructures grown on GaAs (100) substrate with a 200 nm thick GaAs buffer layer has high-dot density (4.68 x 1010 cm-2) and more uniform dot size. Increasing and decreasing of the buffer layer thickness causes the density of small dots to be reduced with several large dots (nano-islands) distributed randomly on the surface. The GaAs buffer and spacer layer thickness in the growth of In0.5Ga0.5As nanostructures has important effect on the dots formation.