Facet Formation of Uniform InAs Quantum Dots by Molecular Beam Epitaxy

Abstract

Uniform InAs quantum dots were grown by molecular beam epitaxy via the Stranski-Krastanov (SK) growth mode, and the self-size-limiting effects due to facet formation were investigated. The facet formation of the 3D dots depends on the growth conditions. As the growth rate and the arsenic pressure decrease, the crystal orientation of the facet changes from the {136} plane to the {101} plane. After the self-size-limiting effects due to the facet formation, the surface concentration of indium adatoms increases, and the density of the coalescent dots also increases. The low arsenic pressure and the low growth rate are effective conditions for suppressing the coalescence and reducing the size fluctuation of the coherent 3D dots. As a result, it was found that the uniform formation of the InAs quantum dots can be achieved by conventional SK-mode growth under low growth rate and low arsenic pressure conditions.