The growth of thin Bi₂Se₃ films on (0001) sapphire substrates by metalorganic chemical vapor deposition (MOCVD) was investigated. A two-heater configuration was employed to pre-crack the metalorganic sources upstream of the substrate while maintaining a low substrate temperature (<250°C). Epitaxial Bi₂Se₃ films with (006) x-ray rocking curve full-width-at-half-maximum values on the order of 160 arcsecs were obtained at growth rates of ~6 nm/min or lower while higher growth rates resulted in polycrystalline films. The background electron concentration of the films was found to depend strongly on the substrate temperature and Se/Bi inlet ratio. Bi₂Se₃ films with a room temperature electron concentration of 6.7x10¹⁹ cm^-3 and mobility of 155 cm²/Vs were obtained at 200°C with a Se/Bi ratio of 80. Higher substrate temperature and lower Se/Bi ratios resulted in an increase in electron concentration and corresponding reduction in mobility. The results demonstrate the potential of MOCVD for the growth of Bi₂Se₃ and related materials for topological insulator studies.

Date Published: 16 September 2014
PDF: 6 pages
Proc. SPIE 9174, Nanoepitaxy: Materials and Devices VI, 91740H (16 September 2014); doi: 10.1117/12.2065151

Published in SPIE Proceedings Vol. 9174:
Nanoepitaxy: Materials and Devices VI
Nobuhiko P. Kobayashi; A. Alec Talin; Albert V. Davydov; M. Saif Islam, Editor(s)