ZnO film growth on (01(1)over-bar2)LiTaO3 by electron cyclotron resonance-assisted molecular beam epitaxy and determination of its polarity

Single-crystal ZnO films were grown on (01 (1) over bar 2)LiTaO3 substrates by electron cyclotron resonance-assisted molecular beam epitaxy (ECR-assis ted MBE). The film orientation differed with the ratio of oxygen to zinc. U nder oxygen-rich conditions, (11 (2) over bar 0)ZnO films with the c-axis p arallel to the substrate surface were epitaxially grown. To identify the po larity of ZnO films with the c-axis parallel to the surface, a method using sideways chemical etching was proposed. The polarity of ZnO films was diff erent when the films were grown on the + plane or the - plane of (01 (1) ov er bar 2)LiTaO3 substrates. The ZnO/LiTaO3 substrates offer a high electrom echanical coupling factor of the shear horizontal-type leaky surface acoust ic wave (SH-type leaky SAW) propagating along the X-axis due to an addition al contribution of the piezoelectric shear effect of ZnO.