Tuning the bulk conducting states of the topological insulator Bi2Se3
Bi2Se3 is a benchmark thermoelectric material for near room temperature applications. With its first studies reported early in the 60's, it has once again reached the spotlight as the first 3D topological insulators with a single Dirac cone giving rise to topologically protected surface states, that coupled with a large predicted band gap, could enable applications even at room temperature. Further exploration of these surface states has proven to be difficult as bulk conducting states inevitably appears from defects in crystal lattice, hindering the effects of the massless Dirac fermions. As a congruently melting phase, Bi2Se3 can be obtained from a liquid melt with very different Bi-Se proportions, thus by changing the growth procedure, the charge carrier properties can be tuned. In this dissertation, the bulk conducting states of pure Bi2Se3, obtained in the full range of Bi-Se proportions, have been probed by means of resistivity, Hall effect and the Shubnikov-de Haas quantum oscillations of the magnetoresistance.