We report on the growth and modulation of silicon carbide nanowires (SiC NWs). The NWs were fabricated by chemical vapor deposition (CVD) process, and had diameters of less than or equal to 50 nm and length of several pm. X-ray diffraction and transmission electron microscopy analysis showed the single crystalline nature of NWs with a growth direction of <1 1 1>. In-situ modulation of NWs such as self-alignment of NWs on the graphite or silicon substrates, creation of homo interfaces in the NWs by the formation of twins, and doping of aluminum into NWs was also achieved by controlling the processing conditions in the CVD process. Growth and modulation of single crystalline SiC NWs could helpful to meet the requirements for the fabrication of SiC NW-based nanodevices. (C) 2004 Elsevier B.V. All rights reserved.