Optical measurement of the converse piezoelectric d33 coefficients of bulk and microtubular zinc oxide crystals

Zinc oxide (ZnO) crystal is a semiconductor material; the direct measurement and the interpretation of its piezoelectric coefficients are challenging. In this letter, the authors investigate the piezoelectric properties (d33 coefficient) of a bulk ZnO sample by measuring its converse piezoelectric effect using an optical method. The experimental data agree with recent theoretical calculations. The piezoelectric properties of a ZnO hexagonal microtube, which has a highly symmetrical hexagonal tubular structure, are also studied. The results demonstrate that the microtubular ZnO has significantly different piezoelectric properties from that of ZnO bulk crystal, especially under the applied electric fields of low frequencies.