Crescimento e caracterização de nanofios auto-sustentados de ligas ternárias de InGaAs

Abstract

Nanowires of ternary alloys Gallium Arsenide and Indium , are excellent candidates for technological applications in electronic and optoelectronic devices, but there are few experimental studies on growth that achieve a significant knowledge and control of their optical and electrical properties. This thesis presents the results obtained from experimental and theoretical studies of the growth of self-sustained one-dimensional nanostructures (nanowires) of the ternary alloys, , with mole fractions of . The nanowires were grown by the technique of Molecular Beam Epitaxy (MBE) on the GaAs substrate (111) B and (111)B using colloidal gold (Au) nanoparticles as catalysts. Four series of samples of nanowires of ternary alloys with different molar fractions of were grown and characterized in this work. The morphology, chemical composition and crystal structure of the nanowires were characterized using the techniques of scanning electron microscopy (SEM) and Raman spectroscopy. Using SEM it was possible to analyze the dependence of the rate of growth of the nanowires with the variations of its diameter, and thus, understanding the mechanisms of growth of nanowires. The Raman spectroscopy measurements allow to analyze the chemical composition of each of the samples as well as deformations in the crystalline structure of the nanowires. Comparisons of the chemical compositions of different samples of the nanowires grown on different substrates and thin films, grown under the same conditions, allowed sinking into the knowledge of the mechanisms of growth