Defects in semipolar (112?2?) ZnO grown on (112) LaAlO _3/(La,Sr)(Al,Ta)O_3 substrate by pulsed laser deposition

摘要

The microstructure of semipolar(112?2?) ZnO deposited on (112) LaAlO_3/(La,Sr)(Al,Ta)O_3 was investigated by transmission electron microscopy. The ZnO shows an in-plane epitaxial relationship of [112?3]ZnO k [111?]LAO=LSAT with oxygen-face sense polarity. The misfit strain along [112?3]ZnO and [1100?]ZnO is relieved through the formation of misfit dislocations with the Burgers vectors b 1=6/1;112?3]ZnO and b 1=3/1〈1210〉ZnO, respectively. The line defects in the semipolar ZnO are predominantly perfect dislocations, and the dislocation density decreases with increasing ZnO thickness as a result of dislocation reactions. Planar defects were observed to lie in the M-plane and extend along 〈0001〉, whereas basal stacking faults were rarely found.