A simple route to the synthesis of single crystalline copper metagermanate nanowires

Single crystalline copper metagermanate (CuGeO₃) nanowires with the diameter of 30–300 nm and length of longer than 100 µm have been prepared by a simple hydrothermal deposition route. X-ray diffraction (XRD), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM) and Raman analyses confirm that the nanowires are orthorhombic single crystals with a main growth direction along <101>. Room temperature photoluminescence (PL) measurement shows a strong blue emission peak at 442 nm with a broad emission band. The blue emission may be ascribed to radiative recombination of oxygen vacancies and oxygen–germanium vacancies. The formation process of CuGeO₃ nanowires is also discussed.