Peter Grünberg Institute 9 (PGI-9) and
JARA-Fundamentals of Future Information Technologies (JARA-FIT), Forschungszentrum
Jülich, 52425 Jülich, Germany
D. Stange
Peter Grünberg Institute 9 (PGI-9) and
JARA-Fundamentals of Future Information Technologies (JARA-FIT), Forschungszentrum
Jülich, 52425 Jülich, Germany
D. Rainko
Peter Grünberg Institute 9 (PGI-9) and
JARA-Fundamentals of Future Information Technologies (JARA-FIT), Forschungszentrum
Jülich, 52425 Jülich, Germany
M. Virgilio
Dipartimento di Fisica “E. Fermi,” Università di
Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
D. Buca
Peter Grünberg Institute 9 (PGI-9) and
JARA-Fundamentals of Future Information Technologies (JARA-FIT), Forschungszentrum
Jülich, 52425 Jülich, Germany
We report on the direct observation of lattice relaxation and Sn segregation of GeSn/Ge/Si heterostructures under annealing. We investigated strained and partially relaxed epi-layers with Sn content in the 5 at. %-12 at. % range. In relaxed samples, we observe a further strain relaxation followed by a sudden Sn segregation, resulting in the separation of a β-Sn phase. In pseudomorphic samples, a slower segregation process progressively leads to the accumulation of Sn at the surface only. The different behaviors are explained by the role of dislocations in the Sn diffusion process. The positive impact of annealing on optical emission is also discussed.
