Low-Temperature Heteroepitaxial Growth of Single-Domain V-Doped ZnO Films on c-Face Sapphire

High-quality single-domain (ZnO[11–20]//Al₂O₃[10–10]) ZnO heteroepitaxial growth on c-face sapphire [Al₂O₃(0001)] substrate at low temperature was investigated by vanadium (V) doping at growth temperatures between 150°C and 450°C using radiofrequency (RF) magnetron sputtering. In low-temperature growth at 150°C and 200°C, 30° twisted domains (ZnO[10–10]//Al₂O₃[10–10]) were eliminated and good in-plane crystal orientation was obtained for V doping of about 2 at.% to 3 at.%. Single domains were grown from the early stage. From the changes of surface morphology and growth rate, it was considered that migration during the growth was enhanced due to the increase of the diffusion energy of adatoms, while random nucleation was suppressed.