The influence of different indium-composition profiles on the electronic structure of lens-shaped In_xGa_1−xAs quantum dots

Abstract

We present effective-mass calculations of the bound-state energy levels of electrons confined inside lens-shaped In x Ga1−x As quantum dots (QDs) embedded in a GaAs matrix, taking into account the strain as well as the In gradient inside the QDs due to the strong In segregation and In-Ga intermixing present in the In x Ga1−x As/GaAs system. In order to perform the calculations, we used a continuum model for the strain, and the QDs and wetting layer were divided into their constituting monolayers, each one with a different In concentration, to be able to produce a specific composition profile. Our results clearly show that the introduction of such effects is very important if one desires to correctly reproduce or predict the optoelectronic properties of these nanostructures.

Deep level centers and their role in photoconductivity transients of InGaAs/GaAs quantum dot chains

“…INTRODUCTION Self-assembled (In,Ga)As quantum dots (QDs) and quantum wires (QWRs) are perspective candidates for application in novel electronic and optoelectronic systems, e.g., semiconductor lasers, 1 infrared photodetectors, 2 and solar cells 3,4 due to their novel characteristics resulting from quantum confinement. Even though, the optical and electrical properties of such confined systems are largely determined by the electronic spectrum of the (In,Ga)As QDs, the influence of the two-dimensional wetting layer (WL) states and interface states can be significant.…”

High-resolution X-ray diffraction in crystalline structures with quantum dots

“…Also, the model of spheroidal QDs fairly well approximates frequently occurring QDs in the form of a lens [100]. The above approach was used to simulate the diffuse scattering intensity distribution from an array of buried InAs QDs of different shapes in a GaAs basic matrix.…”

“…Quantum dots, especially in the case of their high density in the growth plane, most frequently form a short-range order characteristic of lateral square lattices with the principal axes in the [100] and [010] directions. As mentioned above, square lattices have been produced from long-range-order nanostructures on specially prepared substrates with a periodic relief, referred to as quantum dot crystals [89±91].…”

Photoconductivity Relaxation Mechanisms of InGaAs/GaAs Quantum Dot Chain Structures

“…Such an interest caused by self-assembled (In,Ga)As quantum dots (QDs) and quantum wires (QWRs) are perspective candidates for application in novel electronic and optoelectronic systems, e.g., semiconductor lasers [2], infrared photodetectors [3], and solar cells [4, 5]. This is possible due to quantum confinement, energy disorder, complex electronic spectra of the system, and coexistence of 2D and 1D states.…”