Growth and electrical properties of nonpolar and polar Ga-doped ZnO thin films on LaAlO3 and SrTiO3 substrates

► Nonpolar a-plane GZO thin films are grown epitaxially on LAO (1 0 0) substrates. ► The polar c-plane or the coexistence of c- and a-plane is observed in the GZO thin films on STO (1 0 0). ► Electrical properties of the GZO thin films are deeply affected by the growth orientation. ► GZO films with a-axis oriented phase show higher resistivity than with c-oriented phase. ► The lower mobility of the a-axis oriented GZO films can be ascribed to grain boundary scattering.