Substrate effect on the Young’s modulus measurement of TiO2 nanoribbons by nanoindentation

Abstract

The Young’s modulus of single crystalline rutile TiO2 nanoribbons was investigated using nanoindentation. During the experiments, the nanoribbons were laid on three different substrates, including 1 μm thick SiO2 layer on silicon (SiO2/Si), Si(100), and sapphire(0001). Experimental results show the substrates have significant effects on load-indenter displacement curves. To further understand the experimental findings, three-dimensional finite element modeling was carried out to simulate the indentation of nanoribbon-on-substrate systems using ABAQUS. The results show that the receding contact mechanics is a good approximation when describing the contact between the nanoribbon and the substrate. The results also demonstrate that the substrate effect must be carefully considered when performing nanoindentation on one-dimensional nanostructures. Otherwise, the Young’s modulus of the nanostructures could either be overestimated or underestimated. The Young’s modulus is about 360 GPa, comparable to that of bulk TiO2.