Effect of In_xGa_(1-x)As Underlying Layer andGrowth Mode on the Surface Morphology ofIn_(0.5)Ga_(0.5)As/GaAs Quantum Dots

摘要

Single layer of In_(0.5)Ga_(0.5)As/ quantum dots (QDs) was grown using self-assembled Stranski-Krastanow on a thin In_(0.5)Ga_(0.5)As underlying layer and on a reference GaAs wafer by metal-organic chemical vapour deposition (MOCVD). The effect of different indium composition in the underlying layer and the duration of arsine (A_sH_3) flow during cooling-down period of the growth process were investigated and characterized using atomic force microscopy (AFM). The growth of the thin underlying layer has significant influence on the formation of the QDs on the top surface. The dots density increases with increasing indium composition in the underlying layer. AsH3 flow during the period was found to influence the nucleation process of In_(0.5)Ga_(0.5)As, QDs. A shorter period of A_sH_3 flow promotes smaller dots size and therefore increases the dots density.