Spontaneous growth and phase transformation of highly conductive nickel germanide nanowires
Higgins, Jeremy M.
Faber, Matthew S.
Lee, Pooi See
Date of Issue2011
School of Materials Science and Engineering
We report the synthesis, phase transformation, and electrical property measurement of single-crystal NiGe and ε-Ni5Ge3 nanowires (NWs). NiGe NWs were spontaneously synthesized by chemical vapor deposition of GeH4 onto a porous Ni substrate without the use of intentional catalysts. The as-grown NWs of the orthorhombic NiGe phase were transformed to the hexagonal ε-Ni5Ge3 phase by thermal annealing induced Ni enrichment. This controllable conversion of germanide phases is desirable for phase-dependent property study and applications, and the observation of novel metastable ε-Ni5Ge3 phase suggests the importance of kinetic factors in such nanophase transformations. Electrical studies reveal that NiGe NWs are highly conductive, with an average resistivity of 35 ± 15 μΩ·cm, while the resistivity of ε-Ni5Ge3 NWs is more than 4 times that of the NiGe phase. NWs of nickel germanides, particularly NiGe, would be useful building blocks for germanium-based nanoelectronic devices.
© 2011 American Chemical Society.