High-temperature strength and dislocation mobility in the wide band-gap ZnO: Comparison with various semiconductors

The mechanical strength of bulk single crystal wurtzite ZnO was investigated at elevated temperatures by means of compressive deformation. The yield stress of ZnO in the temperature range of 650-850 °C was found to be around 10-20 MPa, i.e., extremely lower than that of GaN, a typical wide band-gap semiconductor. On the basis of the observed temperature dependence of yield stress, the activation energy for dislocation motion at elevated temperatures in ZnO is deduced to be 0.7-1.2 eV, which follows the relation of activation energy for dislocation motion versus band-gap energy known in a variety of semiconductors.