Kolomys A. Surface morphology and optical property of (In,Ga)As/GaAs and InAs/AlSb nanostructures

Сomplex investigation of the optical and structural properties of multilayer InxGa1-xAs/GaAs structures with quantum dots and wires and of InAs/AlSb heterostructures with quantum wells is presented. The improved physical model of the process of InxGa1-xAs quantum dots formation in multilayered InxGa1-xAs/GaAs structures which explains all photoluminescence, Raman, X-ray and AFM result is proposed. It is shown that the process of the quantum dots (nanoislands) nucleation is not merely the classical Stranski-Krastanov growth mode, but is significantly modified by the vertical segregation of the In atoms and vacancy-assisted interdiffusion of the Ga atoms. It is shown that by careful selection of growth conditions one can achieve the lateral ordering of quantum dots in the very first periods of multilayered InхGa1-хAs/GaAs structures. With the increase of period's number, the degree of lateral ordering and uniformity of quantum dots is improved. It is accompanied by the increase of the degree of polarization of radiation quantum dots. It is found that in the case of InSb-like interface in InAs/AlSb structure the concentration of 2D electrons in InAs quantum wells decreases and their mobility increases. Revealed are considerable concentration changes for 2D electrons at low temperatures in dependency of the excitation quantum energy. Keywords: quantum dot, quantum wire, interdiffusion, strain, plasmon-phonon mode.