With ZnO nanorods doped in only one poly（vinyl alcohol）（PVA） layer,we observed different threshold voltages with reverse DC voltages for a liquid crystal cell.The length and diameter of the ZnO nanorod used in our experiment were about 180 nm and 20 nm,respectively.When the PVA layer on the anodic side was doped, the threshold voltage was larger than that of the pure cell;conversely,when the PVA layer on the cathodic side was doped,the threshold voltage was smaller than that of the pure cell.These results can be explained by the internal electric field model.We also observed a resonance phenomenon with a low frequency AC voltage.
