Effects of Growth and Annealing Temperatures on the Structural and the Optical Properties of In<SUB>0.6</SUB>Al<SUB>0.4</SUB>As/Al<SUB>0.4</SUB>Ga<SUB>0.6</SUB>As Quantum Dots

Abstract

In0.Al0.4As/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 °C, it shifted toward lower energy above 700 °C. The structural and the optical properties of In0.6Al0.4As/Al0.4Ga0.6As QDs were affected by the growth and annealing temperatures.