A simple approach to polytypes of SiC and its application to nanowires

SiC polytypes in bulk form and nanowire are systematically investigated using our empirical potential that is based oil a simple approach, and which incorporates electrostatic energies due to bond charges and ionic charges. Using the empirical potential, the system energies of 3C (zinc blende), 6H, 4H and 2H (wurtzite) structured SiC in bulk form are calculated and compared with ab initio calculations and experimental results. Our calculated results reveal that 3C-SiC is the most stable while 2H-SiC is unstable among these structures at 0 K. This is consistent with experimental results. The appearance of polytypes in bulk form is qualitatively discussed by considering ionicity of semiconductors based oil our simple approach. Furthermore, we clarify the versatility of our simple approach to nanostructures considering SiC nanowire. Hexagonal SiC nanowire stabilizes a 2H structure in the diameter range of D < 20 (nm), whereas 3C-SiC is stabilized only at a large diameter range beyond 20 (nm). This is also consistent with experimental findings for InAs and InP nanowires. SiC polytypes in nanowire are discussed in terms of the ratio of the number of surface dangling bonds to the total number of interatomic bonds. (c) 2005 Elsevier B.V. All rights reserved.