Systesis of topological insulators by chemical vapor deposition

Abstract

Consulta en la Biblioteca ETSI Industriales (Riunet)

[EN] In recent years, some insulators have shown exotic metallic states on their surfaces. These type of materials, named topological insulators, can be defined as a new state of the quantum matter with an insulating bulk gap and massless Dirac surface states, topologically protected by time reversal symmetry. Topological insulators have recently emerged as one of the most researched areas in condensed matter physics, which may provide new pathways to generate and develop the next generation of novel electronics, optoelectronics, energy conversion devices and catalytic chemistry, due to their many remarkable properties. This study is focused on the synthesis of Bi2Se3 topological insulators by chemical vapor deposition (CVD). Muscovite mica and SiO2/Si were used as the substrates. Different temperatures (400--¿500 °C), flow rates (20--¿500 sccm), pressures (33--¿250 Pa), growth times (5--¿120 min) and distances to the center of the furnace (5--¿15 cm) were tested. The results showed that different mechanisms were followed depending on the substrate used. Epitaxial growth was observed in mica substrates, obtaining uniform nanosheets and nanoplates, whereas particles with random shape and orientation were observed when SiO2/Si were used. Epitaxial single--¿crystalline phases are more suitable for future applications. However, mica substrates showed many difficulties for characterization. XRD, TEM, SEM and Raman suggested the Bi2Se3 rhomboedral microstructure of the synthesized particles in SiO2/Si.