Ultrahigh Recovery of Fracture Strength on Mismatched Fractured Amorphous Surfaces of Silicon Carbide.

Author(s) Cui, J.; Zhang, Z.; Jiang, H.; Liu, D.; Zou, L.; Guo, X.; Lu, Y.; Parkin, I.P.; Guo, D.
Journal ACS Nano
Date Published 2019 Jun 06
Abstract

Nanowires (NWs) have been envisioned as building blocks of nanotechnology and nanodevices. In this study, NWs were manipulated using a weasel hair and fixed by conductive silver epoxy, eliminating the contaminations and damages induced by conventional beam depositions. The fracture strength of the amorphous silicon carbide was found to be 8.8 GPa, which was measured by in situ transmission electron microscopy nanomechanical testing, approaching the theoretical fracture limit. Here, we report that self-healing of mismatched fractured amorphous surfaces of brittle NWs was discovered. The fracture strength was found to be 5.6 GPa on the mismatched fractured surfaces, recovering 63.6% of that of pristine NWs. This is an ultrahigh recovery, due to the limits of reconstruction of dangling bonds on the fractured amorphous surfaces and the mismatched areas. Simulation by molecular dynamics showed fracture strength recovery of 65.9% on the mismatched fractured amorphous surfaces, which is in good agreement with the experimental results. Healing on the mismatched fractured amorphous surfaces is by reorganization of Si-C bonds forming Si-C and Si-Si bonds. The potential energy increases 2.6 eV in the reorganized Si-C bonds and decreases by 3.2 and 1.9 eV, respectively, in the formed Si-C and Si-Si bonds. These findings provide insights for the reliability, design, and fabrication of high performance NW-based devices, to avoid catastrophic failure working in harsh and extreme environments.

DOI 10.1021/acsnano.9b02658
ISSN 1936-086X
Citation Cui J, Zhang Z, Jiang H, Liu D, Zou L, Guo X, et al. Ultrahigh Recovery of Fracture Strength on Mismatched Fractured Amorphous Surfaces of Silicon Carbide. ACS Nano. 2019.

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