title: Strain and stability of ultrathin Ge layers in Si/Ge/Si axial heterojunction nanowires.
abstract: The formation of abrupt Si/Ge heterointerfaces in nanowires presents useful possibilities for bandgap engineering. We grow Si nanowires containing thick Ge layers and sub-1 nm thick Ge "quantum wells" and measure the interfacial strain fields using geometric phase analysis. Narrow Ge layers show radial compressive strains of several percent, while stress at the Si/Ge interface causes lattice rotation. High strains can be achieved in these heterostructures, but we show that they are unstable to interdiffusion.
authors: Department of Materials Science and Engineering, National Taiwan University , Taipei 10617, Taiwan.
authors: Cheng-Yen
authors: CY
authors: Wen
authors: Mark C
authors: MC
authors: Reuter
authors: Dong
authors: D
authors: Su
authors: Eric A
authors: EA
authors: Stach
authors: Frances M
authors: FM
authors: Ross
keywords: Nanowire heterostructures; abrupt interfaces; germanium; silicon; strain distribution; structural instability