Synthesis of indium oxide nanorods on indium phosphide substrate using plasma immersion ion implantation

We report the preparation of indium oxide (In₂O₃) nanorods on indium phosphide (InP) substrate by plasma immersion ion implantation (PIII). The InP substrate was first treated with PIII of acetylene (C₂H₂) ions, then followed by coating the surface with a 40 nm thick gold film. After rapid thermal anneal (RTA) at 750 °C for 15 s, In₂O₃ nanorods were found on InP surface. The In₂O₃ nanorods with diameters of 50-200 nm were examined by Raman spectroscopy, scanning electron microscopy (SEM) and cathodoluminescence (CL). Nanoparticles of gold were found at the tip of the nanorods, suggesting that a vapour-liquid-solid (VLS) mechanism was involved. However, the fact that other species such as nitrogen, argon or oxygen would not lead to the formation of In₂O₃ nanorods also suggests that the carbon liberated from C₂H₂ plays an important role as a catalyst. Carbon has previously been reported to be a reduction agent for the formation of group III sub-oxides. Such sub-oxides provide the vapour source for the growth of nano-materials through further oxidation. © 2006 Elsevier B.V. All rights reserved.