Crescimento e caracterização de pontos quânticos naturais de InAs e In0.5Ga0.5As sobre diferentes orientações cristalográficas do substrato de GaAs. / Characterization of InAs and In0.5Ga0.5As self-assembled quantum dots grown on different crystallographic orientations of GaAs substrate.

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

Self-assembled or self-organized quantum dots (QDs) of InAs and In0.5Ga0.5As were produced on different crystallographic oriented GaAs substrates using Molecular Beam Epitaxy. During the growth process the dots were characterized in situ by means of Reflection High-Energy Electron Diffraction (RHEED). The features of RHEED pattern allowed the determination of the critical thickness, for which the transition 2D-3D occur, as well as the crystallographic planes of island facets. Confirmation of the RHEED observations was done using Atomic Force Microscopy (AFM). This technique allowed also determining the form and dimensions of each QD as well as the density of islands. Optical study of quantum dots was carried out by Photoluminescence (PL). Such characterization allowed us to observe a high dependence of PL peak intensity, peak form and peak position, and an additional lateral confiment at quantum dots was verified in the temperature dependence of PL peak intensity. Polarization measurements presented a strong anisotropy h-plane for self-assembled quantum dots, in agreement with RHEED observations.

ASSUNTO(S)

pontos quânticos high-index miller mbe altos índices de miller quantum dots mbe

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