Epitaxial properties of Al-doped ZnO thin films grown by pulsed laser deposition on SrTiO3(001)

Undoped and Al-doped ZnO films with dopant concentrations of nominally 1% and 10% and a thickness of 100 nm have been grown on SrTiO3(001) by pulsed laser deposition at substrate temperatures between 650 deg. C and 820 deg. C. The epitaxial conditions were examined with high pressure in-situ reflection high energy electron diffraction (RHEED) and ex-situ x-ray diffraction (XRD) measurements in different geometries. The films are highly (1120)-oriented with a lattice mismatch between the SrTiO3[110] direction and the c-axis of about 3%. Atomic force microscopy (AFM) revealed smooth surfaces with a roughness of drms<5 nm and different sized islands