Reduced quantum confinement effect and electron-hole separation in SiGe nanowires

Abstract

Using first-principles methods, we investigate the structural and electronic properties of SiGe nanowires-based heterostructures, whose lattice contains the same number of Si and Ge atoms but arranged in a different manner. Our results demonstrate that the wires with a clear interface between Si and Ge regions not only form the most stable structures but show a strongly reduced quantum confinement effect. Moreover, we, with the inclusion of many-body effects, prove that these nanowires---under optical excitation---display a clear electron-hole separation property which can have relevant technological applications.