Large scale computer simulations of strain distribution and electron effective masses in silicon (100) nanowires

摘要

A multiscale method is proposed to analyze the internal redistribution of tensile strain applied to silicon (100) nanowires and its effect on electron effective masses m*. Nonperiodic, realistic models of unprecedented size containing up to 2.2 × 10~7 atoms (652 × 26 × 26 ran~3) allow the identification of nonuniform redistribution patterns specific to the constraints applied to impose external strain. Depending on how the external strain is imposed, silicon nanowires can show m* behavior similar to strained bulk silicon, or, as a function of nanowire size, can display intrinsic strain large enough that external strain hardly reduces m* further. For nanowire cross section sizes smaller than 8×8 nm~2 quantum confinement leads to an increase in m* which cannot be compensated for by tensile strain.