Fabrication of conducting GeSi/Si micro- and nanotubes and helical microcoils

Conducting micro- and nanotubes and free-standing flexible helical microcoils have been fabricated from strained GexSi1-x/Si heterolayers. The fabrication technique was based on self-rolling of a thin highly strained epitaxial GexSi1-x/Si bifilm detached from the substrate by selective etching of a sacrificial layer in a roll-shaped tube. The obtained tube diameters varied from 10 nm to 13 µm, depending on the thickness and lattice mismatch of the GeSi/Si bilayer. GeSi/Si tubes and helical coils, up to 70 nm in diameter, exhibit good conducting properties and high mechanical strength.