Vapor−Solid−Solid Synthesis of Ge Nanowires from Vapor-Phase-Deposited Manganese Germanide Seeds

We report the sequential synthesis of solid-phase manganese germanide seed particles and crystalline Ge nanowires using low-pressure thermal chemical vapor deposition. Mn was deposited on inert substrates from a gas-phase precursor. Mn particles were converted to solid manganese germanide particles upon exposure to germane gas, and these seed particles directed the one-dimensional growth of Ge nanowires. Growth rates for this vapor−solid−solid process approached 200 nm per minute, and the diameter distribution was tightly clustered around 18 nm. This approach to Ge nanowire growth has at least three attractive features: (1) the seed particle is not Au, avoiding the potentially negative influence of Au impurities on electrical properties; (2) the vapor-phase deposition and self-assembly of the seed greatly simplifies the nanowire synthesis process; and (3) the self-assembled seed naturally produces a narrow distribution of nanowire diameters.