Tesis
Efeito da modulação da topologia do confinamento em sistemas quase zero-dimensionais induzida por campo elétrico
Fecha
2015-04-01Registro en:
OLIVEIRA, Edson Rafael Cardozo de. Modulation effect on confinement topology in quasi zero-dimensional systems induced by electric field. 2015. 102 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2015.
Autor
Oliveira, Edson Rafael Cardozo de
Institución
Resumen
Quantum dots grown by epitaxial techniques for optical and transport studies are usually capped by a layer of the same material on which the QDs were grown. Recently, several studies have shown how the growth parameters and materials used in this layer significantly affect the morphological, optical and electrical properties of these nanostructures. In this work Indium Arsenide quantum dots capped with a layer of Gallium Arsenide and Antimony are studied. After the growth, a rapid thermal annealing was performed, which improved significantly the size distribution of the quantum dots, increasing the optical eficiency, and inducing a change in the band structure from a Type-I to Type-II. The investigations performed by magnetophotoluminescence have shown that the effects of the topology confinement on the band structure of these quasi zero-dimensional systems are strongly modulated by an external electric field applied parallel to the magnetic field orientation. Purely quantum effects such as Aharonov-Bohm interference and the inversion of the excitonic Landfie g-factor were observed at low temperatures and for specific values of electric fields, showing that the choice of the material and growth conditions of quantum dots capping layer leads to controlled experimental results which could not be achieved using conventional growth methods of semiconductor quantum dots.