High-quality hybrid-GeSn/Ge stacked-structures by low-temperature Sn induced-melting growth

GeSn alloys are attractive materials, with a potentially major impact on next-generation device applications due to the superior electrical properties and transition to direct band gap. We investigate growth of GeSn by annealing of a-Ge/Sn/c-Ge stacked structures. This achieves liquid-phase epitaxial growth of defectfree GeSn with non-equilibrium Sn concentration (∼2%) on Ge substrates by a low-temperature annealing (∼600°C). The nonequilibrium Sn concentration in this GeSn layers is guaranteed thermal stability for post-annealing at 600°C for 30 min.