Epitaxial growth of InP nanowires on germanium

Abstract
The growth of III–V semiconductors on silicon would allow the integration of their superior (opto-)electronic properties1, 2, 3 with silicon technology. But fundamental issues such as lattice and thermal expansion mismatch and the formation of antiphase domains have prevented the epitaxial integration of III–V with group IV semiconductors4, 5, 6. Here we demonstrate the principle of epitaxial growth of III–V nanowires on a group IV substrate. We have grown InP nanowires on germanium substrates by a vapour–liquid–solid7 method. Although the crystal lattice mismatch is large (3.7%), the as-grown wires are monocrystalline and virtually free of dislocations. X-ray diffraction unambiguously demonstrates the heteroepitaxial growth of the nanowires. In addition, we show that a low-resistance electrical contact can be obtained between the wires and the substrate.