Effects of Growth and Annealing Temperatures on the Structural and the Optical Properties of In0.6Al0.4As/Al0.4Ga0.6As Quantum Dots

Abstract

In0.6Al0.4As/Al0.4Ga0.6As quantum dots (QDs) were grown on GaAs (001) substrates by using molecular beam epitaxy utilizing a modified Stranski-Krastanow method. Atomic force microscopy images showed that the size of the In0.6Al0.4As QDs increased with increasing growth temperature. Photoluminescence spectra at 300 K showed that the exciton peaks corresponding to the interband transitions from the ground electronic subband to the ground heavy-hole subband (E1-HH1) of the In0.6Al0.4As/Al0.4Ga0.6As QDs shifted to large energy side with increasing growth temperature resulting from an increase in the height of the In0.6Al0.4As QDs. While the (E1-HH1) peak position of the PL spectra shifted toward larger energy side with increasing up to an annealing temperature of 700 degrees C, it shifted toward lower energy above 700 degrees C. The structural and the optical properties of In0.6Al0.4As/Al0.4Ga0.6As QDs were affected by the growth and annealing temperatures.