Aging effect of rolled-up InGaAs/GaAs/Cr helical nanobelts

We report an aging effect on as-fabricated InGaAs/GaAs/Cr helical nanobelts. It has been observed that over time the nanobelt diameter first decreases and then increases until a constant value is reached. The gradual change of the diameter of the helical nanobelts from their original value is due to the competition of stress relaxation along the transverse and longitudinal axes of the nanobelts. Finite element modeling (FEM) has been applied to validate the influence of the biaxial stress relaxation on the curvature change of these rolled-up helical nanobelts. In addition, the dependence of the pitch of the helix over time is investigated as well.