The interest in group-IV based optoelectronic devices has increased due to a foreseeable future demand. The main advantage is the relatively simple integration into the modern Silicon-based Complementary Metal-Oxide-Semiconductor technology platform. The ternary alloy Silicon-Germanium-Tin enables achieving a direct bandgap material made from the indirect semiconductors Silicon, Germanium and Tin. By using a virtual Germanium substrate technology these semiconductors can be integrated on a Silicon wafer. In this paper, we discuss the characterization of grown and fabricated pin-diodes made from the ternary alloy Silicon-Germanium-Tin by using Molecular Beam Epitaxy technology on a virtual Germanium substrate formed on Silicon(001) wafers. To achieve higher Tin concentrations to enable direct band transitions, a thin Germanium-Tin layer is inserted into the intrinsic region of the pin-diodes resulting in a quantum well. It is shown that these pin-diodes have electrically good characteristics and in particular a low dark current density, which suggest a high crystal-quality.