Synthesis of Ge-Sn alloys by ion implantation and pulsed laser melting: Towards a group IV direct band gap semiconductor

The GeSn material system is expected to be a direct bandgap group IV semiconductor at a Sn content of 6.5–12 at.%, depending on the level of residual compressive strain in the alloy films [1]. Such Sn concentrations can only be realized by non-equilibrium preparation techniques since the equilibrium solubility of Sn in Ge is around 0.5 at.% at room temperature [2]. In this presentation, the combination of ion implantation and pulsed laser melting (PLM) is demonstrated to be a promising alternative method to molecular beam epitaxy (MBE) and chemical vapour deposition (CVD) techniques to produce highly Sn concentrated alloys with good crystal quality.