Segregation, quantum confinement effect and band offset for [110] SiGe NWs

Results of first-principles DFT simulations provide strongevidence that, at zero temperature, for [110] oriented SiGenanowires (NWs), the segregated structure is favoured withrespect to the mixed ones; for this observation two differentschemes of calculations are presented and discussed. Moreoverthe segregation strongly influences the NWs electronic properties,inducing a reduced quantum confined effect (RQCE). Weshow here that it depends on the effect of strain in the planenormal to the direction of growth and not on the choice of latticeparameter in the direction of growth.Aqualitative evaluation ofthe band offset between Si and Ge for SiGe NWs is alsopresented.