Stress control of tensile-strained In1-xGaxP nanomechanical string resonators
Appl. Phys. Lett., vol. 113, no. 20, pp. 201903 (2018).
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We investigate the mechanical properties of freely suspended nanostrings fabricated from tensile-stressed, crystalline In1-xGaxP. The intrinsic strain arises during epitaxial growth as a consequence of the lattice mismatch between the thin film and the substrate, and is confirmed by x-ray diffraction measurements. The flexural eigenfrequencies of the nanomechanical string resonators reveal an orientation dependent stress with a maximum value of 650 MPa. The angular dependence is explained by a combination of anisotropic Young’s modulus and a change of elastic properties caused by defects. As a function of the crystal orientation, a stress variation of up to 50% is observed. This enables fine tuning of the tensile stress for any given Ga content x, which implies interesting prospects for the study of high Q nanomechanical systems.
1 Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
2 Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, A-1090 Vienna, Austria
3 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, D-12489 Berlin, Germany
4 Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany