The Study Of Optical Properties On InAs Self-organized Quantum Dots

Quantum dots (QDs), with zero-dimensional electronic properties, have stimulated great interest due to their important roles in fundamental physical research and for developing novel devices. In recent years, it has been one of frontier topics of materials science to study the characterization of self-organized quantum dots and device applications. GaAs-based In(Ga)As self-organized QDs have become another promising gain material for optical fibre communication other than InP-based semiconductor lasers due to relatively inexpensive cost and maturity of fabrication on devices. In this thesis, high quality GaAs-based InAs self-organized QDs were grown by molecular-beam epitaxy (MBE). The QDs were systematically researched by atomic force microscopy (AFM), scanning electric microscopy (SEM), temperature -dependent and time resolved-photoluminescence (TDPL and TRPL). Results are summarized as follows:1. The influences of a thin In0.1Ga0.9As layer(5 nm) grown on GaAs(100) substrate before deposited InAs QDs were experimentally investigated. It is shown that In0.1Ga0.9As strained layer could release the strain between wetting layer (WL) and QDs, and then significantly increased the density of QDs. When the InAs layer was thinner, the QDs are chained and strong coupled with adjacent dots. The photoluminescence peaks of InAs QDs with In0.1Ga0.9As(emitting at above 1.3μm.) show much red shift compared with the QDs directly deposited on GaAs matrix.2. Firstly, the relations between the density and size of QDs and their PL lifetimes have been studied. The results showed that the PL life was insensitive to the temperature below 50 K, and then increases with the temperature until a...