The well aligned boron nanowires (BNWs) with single crystalline structure were successfully prepared by using nanochannel-Al2O3 as a substrate and a chemical vapor deposition process. The diameter and length of BNWs were around of 40 nm and several micrometers, respectively. The formation of single crystal BNWs has been conceptually interpreted. (C) 2003 Elsevier B.V. All rights reserved.