Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 92: Postersession DS/HL

HL 92.30: Poster

Donnerstag, 10. März 2016, 16:00–19:00, Poster A

The study of interaction, nonlinear and dissipation effects in nanomembranes by investigating the dispersion relations of bending waves — •Fan Yang, Elke Scheer, and Reimar Waitz — Universitaetsstrasse.10 Fach 681, 78457 Konstanz, Germany

Deciphering the mode shapes of vibrations of nanopatterned membranes is paving the way for applications of nanoscale membrane which rely on particular properties of vibrational excitations. The mode shape of bending waves in thin silicon, silicon carbide, silicon nitride and ultrathin carbon nanomembranes is measured as a function of space and time, using a phase-shift interferometer with continuous and stroboscopic light [1,2]. We develop a method to obtain the contribution of the membrane itself, the eigen-frequencies and the Q factor of the membrane. The contributions of a superposition of the mode corresponding to the excitation frequency and several higher harmonics can be separated and be imaged up to the eighth harmonic of the excitation frequency. We can determine the dispersion relation of membrane oscillations in a frequency range from ground mode up to 12 MHz. The study of the temperature-dependent vibration behavior reveals an unexpected temperature dependence of the mechanical properties of a prestressed nanomembrane. At variance to expectations based on classical continuum mechanics we observe that Young's modulus increases with increasing temperature.

[1] R. Waitz, et al., Phys. Rev. B 86, 039904 (2012).

[2] X. H. Zhang, et al., Appl. Phys. Lett. 2015, 106(6): 063107.