Bringing the photoplastic effect in ZnO to light: A photoindentation study on pyramidal slip

The external light environment has been reported to have a pronounced influence on the dislocation-based plasticity in various inorganic semiconductors. Herein, with a specific focus on the pyramidal slip in wurtzite structures, photoindentation tests were performed on the (0001) plane of ZnO crystal to activate the pyramidal slip and evaluate the effects of light on dislocation behaviors. Statistical analyses of the first pop-in events suggested that the corresponding maximum shear stresses in darkness were slightly smaller than those in 405 nm light, indicating a minor effect of light on dislocation nucleation event. Regarding nanoindentation creep tests, light illumination was found to suppress the indentation depth. Further transmission electron microscopy observations demonstrated that indentation-induced pyramidal dislocations were present deeper in darkness than in 405 nm light, revealing a suppressive effect of light illumination on the pyramidal slip in ZnO for the first time.

Automated summary

The external light environment has a pronounced influence on the dislocation-based plasticity in inorganic semiconductors. Light illumination affects the formation and slip of dislocations, and the impact varies with different wavelengths.