A record-high mobility of holes, reaching 4.3 × 106 cm2 V?1 s?1 at 300 mK in an epitaxial strained germanium (s-Ge) semiconductor, grown on a standard silicon wafer, is reported. This major breakthrough achieved due to the development state-of-the-art growth technology culminating superior monocrystalline quality s-Ge material platform with very low density background impurities and other imper...