InGaN nanowires (NWs) were grown on Si(100) at 700 degrees C using Au catalyst in a plasma-assisted chemical vapor deposition reactor. As the indium vapor pressure was low around 16 mPa during the growths, only the curved GaN NWs could be grown containing indium impurities. By increasing the indium vapor pressure to 53 mPa during the growths, InGaN NWs were transformed to less curved NWs with a broad distribution of NW diameters from 20 to 90 nm. The room temperature photoluminescence of InGaN NWs grown at a high indium vapor pressure showed a broad emission peak at 417 nm, corresponding to an average of 14.5% indium composition in the NWs, with a large full-width at half maximum of 77 nm. Transmission electron microscopy characterization of InGaN NWs showed that the growth orientation was along [100] for the low indium vapor pressure growths and was transformed to along [001] for the high indium vapor pressure growths. (C) 2014 Elsevier B. V. All rights reserved.