Study on the non-linear property of abnormally grown grain ZnO

Abnormally grown large size ZnO grains were prepared by applying a specific uniaxial pressure on the additive-free ZnO compact specimen. The average grain size was larger than 500 μm after heat treatment at 1490 °C for 4 h in air atmosphere. The crystallographic examination was performed using X-ray diffraction (XRD) and electron back scatter diffraction (EBSD) and the current–voltage characteristics were measured with the aid of microscopic probes. These additive-free ZnO grains showed non-linear current–voltage characteristics especially at a high current region. From the several experimental results, we found the origin of the non-linearity can be attributed to the presence of stress within grains which is introduced during the growth procedure.