  Ge1-xSnx and Si1-x-yGeySnx alloys are promising materials for future opto-
and nanoelectronics applications. These alloys enable effective band-gap
engineering, broad adjustability of their lattice parameter, exhibit much
higher carrier mobility than pure Si, and are compatible with the CMOS
technology. Unfortunately, the equilibrium solid solubility of Sn in Si1-xGex
is less than 1% and the pseudomorphic growth of Si1-x-yGeySnx on Ge or Si can
cause in-plane compressive strain in the grown layer, degrading the superior
properties of these alloys. Therefore, post-growth strain engineering by
ultrafast non-equilibrium thermal treatments like pulse laser annealing (PLA)
is needed to improve the layer quality. In this article, Ge0.94Sn0.06 and
Si0.14Ge0.8Sn0.06 thin films grown on silicon-on-insulator substrates by
molecular beam epitaxy were post growth thermally treated by PLA. The material
is analyzed before and after the thermal treatments by transmission electron
microscopy, X-ray diffraction (XRD), Rutherford backscattering spectrometry,
secondary ion mass spectrometry, and Hall effect measurements. It is shown that
after annealing, the material is single-crystalline with improved crystallinity
than the as-grown layer. This is reflected in a significantly increased XRD
reflection intensity, well-ordered atomic pillars, and increased active carrier
concentrations up to 4x1019 cm-3.
