Screw dislocation assisted spontaneous growth of single-crystalline α-Al2O3 microrods

Herein we reported a simple chemical vapor deposition approach to synthesize single crystal α-Al2O3 microrods with diameters of 2-4 μm and lengths of 10-30 μm on the as-prepared SiC-Si-Al2O3 ceramics based on the screw dislocation growth. Two types of evidence for screw dislocation growth have been conclusively observed in the as-synthesized microrods: scanning electron microscopy analysis reveals that the representative morphology feature of the screw dislocation growth is the stepwise spiral terrace configuration and the growth kinetics of the as-synthesized microrods follows the prediction of the dislocation growth mechanism as described by Burton-Cabrera-Frank theory. This work provides not only a new method for synthesizing Al2O3 microrods but also a new insight into the growth mode for Al2O3 microrods.