Crystallography and surface faceting of germanium nanowires

The crystallographic orientation and cross-sectional shape of Germanium Nanowires were analyzed using the high-resolution transmission electron microscopy (HRTEM) and electron diffraction. The Germanium nanowires were synthesized by the gold-nanocrystal-seeded supercritical fluid-liquid-solid (SLFS) method that provides high quality crystalline nanowires. Electron diffraction (ED) patterns obtained from individual nanowires reveal forbidden diffraction spots that occurs due to the surface faceting. The semiconductor nanowires produced by SFLS are faceted with well-defined surface structure, while surface faceting must be included in model structures to predict electronic and optical properties. The nanowires growth direction was determined from ED patterns and Fast Fourier transforms (FFT) of TEM images. The results shows that the accurate determination of the nanowires growth direction requires sample titling to obtain the appropriate crystallographic orientation.