The effect of flash lamp annealing on the crystal growth of amorphous germanium-tin (GeSn) layer deposited on Ge-on-insulator wafer was investigated. It was found that the presence of Sn in the amorphous Ge significantly promoted solid-phase growth (SPG). The diffusion of Sn during the SPG of GeSn was completely suppressed owing to milli-second thermal processing, providing a high-quality GeSn layer with Sn content of 13%, which far exceeds the equilibrium solid solubility limit (∼1%). The fabricated GeSn/Ge-on-insulator wafer exhibited improved infrared absorption beyond 2000 nm, which would be a suitable platform for near-infrared image sensors based on group-IV materials.
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