Evaluation of Thermal Expansion Coefficient in Ge_1-x Sn _x Nanowire Using Reciprocal Space Mapping

Abstract

We evaluated the thermal expansion coefficients in germanium tin (Ge1 - x Sn x ) nanowire and blanket (un-patterned) film formed on Ge (001) substrate by X-ray diffraction measurement with synchrotron radiation. It was found that the thermal expansion coefficients of Ge0.968Sn0.032 are different in directions between parallel and normal to Ge substrate surface. Effect on anisotropy of lattice parameters on the anisotropic thermal expansion coefficient of Ge0.968Sn0.032 is also clarified, and the largest anisotropy was observed in blanket film.

Strain distributions in carbon-doped silicon nanowires along [110] and [100] investigated by X-ray diffraction

“…These nanowires were patterned with periodicities of 5 μm and 15 μm in the shortand long-side directions in square areas of 1.5 mm × 1.5 mm. [32][33][34] As-deposited areas of C-doped Si thin films were retained as references.…”

“…5,6,18,22) These methods give excellent results with very fine spatial resolution but are not suitable for statistical investigations since local and individual characteristics are emphasized By observing samples with many nanowires periodically arranged within a 1.5 mm × 1.5 mm region with X-rays of sub-millimeter beam width, we obtained statistically averaged characteristics while eliminating the effects of individual nanowire differences, as previously reported. [32][33][34] Previously, we found an indication that [100] nanowires were more relaxed than [110] nanowires by assuming that all nanowires have uniform lattice spacings. 34) However, differences between [100] and [110] C-doped Si nanowires were very ambiguous, since spreading RSM profiles in the observations indicate quite large distributions of lattice spacings.…”