Resumo

MENGUI, U. A.; ABRAMOF, E.; RAPPL, P. H. O.  e  UETA, A Y.. Characterization of SnTe films grown by molecular beam epitaxy. Braz. J. Phys. [online]. 2006, vol.36, n.2a, pp. 324-327. ISSN 0103-9733.  http://dx.doi.org/10.1590/S0103-97332006000300024.

A series of SnTe layers with thicknesses varying from 0.42 to 9.1 µm were grown by molecular beam epitaxy on (111) BaF₂ substrates. The SnTe lattice parameter was found to be 6.331 Å as determined from x-ray diffraction spectra measured in the triple-axis configuration. The FWHM of the (222) SnTe x-ray rocking curves indicated a good crystalline quality and an unusual dependence on layer thickness. Atomic force microscopy (AFM) of the SnTe surface revealed spirals with monolayer steps formed around threading dislocations, similar to the PbTe on BaF₂ epitaxy. The dislocation density was estimated from the AFM picture to be 9x10⁸ cm^-2. Small black pits corresponding to holes that were left during growth were also observed on the AFM images. Sn diffusion can be a possible reason for these pits and the relatively high dislocation density. Electrical measurements showed that the SnTe epilayers present a typical p-type carrier concentration around 10²⁰ cm ^{- 3} almost temperature independent and a Hall mobility which decreases from 10⁴ to 10³ cm²/V.s as the temperature increases from 10 to 350K.

Palavras-chave : SnTe; Molecular beam epitaxy; BaF₂ substrates.