Figure 1: Structural characterization of Ge/InAlAs nanocomposite.
(a) Schematic illustration of Ge/InAlAs nanocomposite growth. (b) Three-dimensional APT image of Ge nanowires showing 10% Ge concentration iso-surface (red) and Al atoms (blue). Scale bar, 20 nm. (c) Cross-sectional ADF-STEM and EDX images showing continuous columnar growth of Ge nanowires. Scale bar, 80 nm. (d) Planar-view ADF-STEM and EDX Ge elemental mapping images. Scale bar, 60 nm. (e) Bright-field TEM image under g=(220) two-beam condition shows no evidence of extended defects in a Ge/InAlAs nanocomposite layer sandwiched by InAlAs layers. Scale bar, 50 nm. (f) Cross-sectional Cs-corrected low-angle ADF-STEM image reveals single-crystalline Ge nanowires with fully coherent interfaces. Scale bar, 4 nm. Images b,c were taken from samples with 3.6% Ge, growth temperature=500 °C and images d–f were taken from a sample with 1.4% Ge, growth temperature=520 °C.
