First-principle investigation of strain effects on the electronic properties of germanium nanowires

Abstract

Using the GGA functional in density functional theory, the effects of axial strain on the band structure and effective mass of narrow [110] and [100] germanium nanowires are investigated. It is observed that both compressive and tensile strain cause indirect-to-direct bandgap transitions. One percent of tensile strain can cause a 40 meV change in the bandgap of [110] nanowires. Effective masses of electrons and holes are subject to a change of 3-4 times in the strain-induced transition point. This change translates into a density of state modulation which opens new possibilities for the construction of Ge nanowire-based sensors. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.