Epitaxial and endotaxial semiconductor quantum dots: A brief review on atomic ordering and the void-mediated formation mechanism

Abstract

On the basis of experimental evidence that was presented in earlier original works and reviews, the suggestion is made that atomically ordered quantum dots which are grown by either epitaxy or endotaxy may in addition to their larger quantum confinement potentials possess superior long-term structural stability. Such atomically ordered quantum dots should, therefore, be superior to random alloy quantum dots as far as prospective device applications are concerned. The theoretical basis for this suggestion is simple thermodynamic calculations. The predictions from our simple model are in agreement with high resolution electron phase contrast transmission electron microscopy (HRTEM) and atomic resolution Z-contrast scanning transmission electron microscopy (Z-STEM) observations on epitaxially grown atomically ordered In(Sb,As), (In,Ga)Sb, (Cd,Zn)Se, (Cd,Mn,Zn)Se quantum dots, epitaxial Pb(Se,Te) quantum dot predecessor islands, and endotaxially grown (In,Si,As) quantum dots in Si matrix. Endotaxially grown (Sn,Si) quantum dots in Si matrix are also discussed. It is suggested that the void-mediated formation mechanism of such (Sn,Si) quantum dots in Si may be employed for other endotaxially grown QDs systems.