Elaboration and characterisation of Bi2Se3 thin films using ditertiarybutylselenide as a precursor by MOCVD system

The growth of Bi2Se3 thin films by metalorganic chemical vapour deposition (MOCVD) using trimethylbismuth and a novel Se-precursor: ditertiarybutyl-selenide (DTBSe) as bismuth and selenium sources, respectively, is investigated on pyrex substrates. These films always displayed n-type conduction for a VI/V ratio between 3 and 15. By X-ray diffraction and SEM observation, we noticed the polycrystalline structure of the layers of typical preferential c-orientation and confirmed the hexagonal structure. The microprobe data indicate that the best stoichiometry of Bi2Se3 was achieved. The Seebeck coefficient and the carrier concentration vary slowly with VI/V ratio: -130 to -159.2 muV/K and 2.35 x 10(19) to 6.15 x 10(19) cm(-3), respectively. In contrast, the mobility and the resistivity highly depend on the VI/V ratio. Their values vary from 62 to 225cm(2)/V s and from 9.74 to 17 muOmegam, respectively. These initial results suggest a significant potential for the MOCVD method to produce good thermoelectrical materials using DTBSe as Se-precursor. (C) 2002 Elsevier Science B.V. All rights reserved.