Observation of hole accumulation in Ge/Si core/shell nanowires using off-axis electron holography.
Hole accumulation in Ge/Si core/shell nanowires (NWs) has been observed and quantified using off-axis electron holography and other electron microscopy techniques. The epitaxial [110]-oriented Ge/Si core/shell NWs were grown on Si (111) substrates by chemical vapor deposition through the vapor-liquid-solid growth mechanism. High-angle annular-dark-field scanning transmission electron microscopy images and off-axis electron holograms were obtained from specific NWs. The excess phase shifts measured by electron holography across the NWs indicated the presence of holes inside the Ge cores. Calculations based on a simplified coaxial cylindrical model gave hole densities of (0.4 ± 0.2) /nm(3) in the core regions.
Department of Physics, Arizona State University, Tempe, Arizona 85287-1504, USA. Luying.li@asu.edu
Luying
L
Li
David J
DJ
Smith
Eric
E
Dailey
Prashanth
P
Madras
Jeff
J
Drucker
Martha R
MR
McCartney
D003460:Crystallization / Q000379:methods; D005857:Germanium / Q000737:chemistry*; D006696:Holography / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008854:Microscopy, Electron / Q000379:methods*; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D016062:Porosity; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
D046911:Macromolecular Substances; D005857:Germanium; D012825:Silicon