The formation of dimensionally ordered germanium nanowires within mesoporous silica

Herein is described a supercritical fluid solution-phase method for the synthesis of high aspect ratio nanowires of true nanometre diameter within the pores of an ordered mesoporous material. Using powder X-ray diffraction (PXRD), 29Si MAS–NMR and transmission electron microscopy (TEM), it is possible to show that the quantum confined nanowires formed partially fill the pores of the mesoporous solid and are orientated so that the 〈1 0 0〉 plane of the wires runs parallel to the pore direction. We also show that the wires have an expected diamond-like structure although there is a measurable lattice expansion compared to bulk forms of germanium.