Transformation of epitaxial NiMnGa/InGaAs nanomembranes grown on GaAs substrates into freestanding microtubes

Abstract

We report the fabrication of Ni 2.7 Mn 0.9 Ga 0.4 /InGaAs bilayers on GaAs (001)/InGaAs substrates by molecular beam epitaxy. To form freestanding microtubes the bilayers have been released from the substrate by strain engineering. Microtubes with up to three windings have been successfully realized by tailoring the size and strain of the bilayer. The structure and magnetic properties of both, the initial films and the rolled-up microtubes, are investigated by electron microscopy, X-ray techniques and magnetization measurements. A tetragonal lattice with c/a ¼ 2.03 (film) and c/a ¼ 2.01 (tube) is identified for the Ni 2.7 Mn 0.9 Ga 0.4 alloy. Furthermore, a significant influence of the cylindrical geometry and strain relaxation induced by roll-up on the magnetic properties of the tube is found.

Self‐Rolled‐Up Ultrathin Single‐Crystalline Silicon Nanomembranes for On‐Chip Tubular Polarization Photodetectors

“…[ 6,7 ] 3D self‐assembled freestanding nanomembranes offer a wider range of optical functions and mechanical structural designs than 2D planar materials. [ 8–10 ] Typically, the fabrication process of freestanding 3D single‐crystalline nanomembranes relies on heterogeneous epitaxial techniques with lattice interfaces and artificial termination first, [ 11–14 ] which is often considered as lattice matching. During epitaxial processes, residual strain will be inevitably introduced into epitaxial single‐crystalline nanomembranes via lattice mismatch, which often results in a short lifetime and poor uniformity of planar devices.…”

Fabrication of self-rolling geodesic objects and photonic crystal tubes

“…Beyond the well-known planar technology, an alternative but versatile fabrication method is the self-organization (pattern formation) through pre-stress relaxation in thin films. The pioneering work in [5][6][7][8] was successfully applied to: nanotubes [9][10][11][12], nano-springs [13], helical nano-shape selection and control [14][15][16], nano-shells [6,7,17], etc. Folding planar patterned films for robust realization of 3D photonic crystals was already suggested in [18] while metal-assisted self-folding nanostructures using imprint patterned surfaces was successfully reported in [19].…”