One-dimensional GaN nanostructures are promising materials for nano-device applications. In the present work, we demonstrated the successful growth of GaN NWs on platinum coated Si(1 1 1) substrates. The GaN NWs density and degree of alignment were found to be highly sensitive to the growth temperatures. The GaN NWs were characterized by field-emission scanning electron microscopy (FE-SEM), photoluminescence (PL), cathodoluminescence (CL) and high-resolution transmission electron microscopy (HR-TEM). The density of GaN NWs was increased monotonically with increase in growth temperature. Relatively, high density of GaN NWs was observed for the growth temperature of 950 °C. It was interestingly observed that the peculiar bicrystalline structure of GaN NWs both contain identical crystal structure with a finite interface. We concluded that the Pt acts as a catalyst for GaN NWs growth, and that it provides control over density and position of GaN NWs growth, which can be ultimately utilized for nano-device fabrication. © 2010 Elsevier B.V.