Lattice dislocation in Si nanowires

摘要

Modified formulas were used to calculate lattice thermal expansion, specific heat and Bulk modulus for Si nanowires with diameters of 115, 56, 37 and 22 nm. From these values and Gruneisen parameter taken from reference, mean lattice volumes were found to be as 20.03 A~3 for the bulk and 23.63, 29.91, 34.69 and 40.46 A~3 for Si nanowire diameters mentioned above, respectively. Their mean bonding length was calculated to be as 0.235nm for the bulk and 0.248, 0.269, 0.282 and 0.297 nm for the nanowires diameter mentioned above, respectively. By dividing the nanowires diameter on the mean bonding length, number of layers per each nanowire size was found to be as 230, 104, 65 and 37 for the diameters mentioned above, respectively. Lattice dislocations in 22nm diameter wire were found to be from 0.00324nm for the 1st central lattice to 0.2579nm for the last surface lattice. Such dislocation was smaller for larger wire diameters. Dislocation concentration found to change in Si nanowires according to the proportionalities of surface thickness to nanowire radius ratios.