Análise de nanofios heteroestruturados via microscopia eletrônica de transmissão

Abstract

The semiconductor physics has several technological applications and enables the construction of complex self-organized structures, which can be even free of defects. For this reason the growth of nanowires is an important research line. The objective of this works is to study the growth of III-V semiconductor nanowires and determin the morphology of their heterostructures. The nanowires were grown by the VLS (Vapor – Liquid – Solid) method and show two regions of binary compounds, InAs and InP, and a layer of ternary compound, InAs1-xPx, grown between them. The versatility of this technique, capable of forming heterostructures, is of great importance for allowing, among other things, the formation of quantum wells due to the combination of materials with different electronic properties. These structures can be projected new devices of high performance that exploit physical processes in low dimensional semiconductors. The morphology of the nanowires was analyzed by transmission electron microscopy and chemical composition was mapped using energy dispersive x-ray spectroscopy (EDS). The EDS analysis determined the change in chemical composition in the length of the heterostructure. We also studied the mechanism of growth and functionality of the catalyst. From the analysis, it was observed the growth of the nanowire through the gold nanoparticle and its enlargement by means of vapor-solid deposition. It was observed the presence of a greater amount of arsenic at the interface nanoparticle/nanowire resulting from the expulsion of the element during solidification of the nanoparticle.