A-plane sapphire: A well-matched substrate for epitaxial growth of indium tin oxide

Indium tin oxide (ITO) thin films were grown on the (112̄0) surface of sapphire using fast-pulse laser deposition. It was found that when the oxygen pressure was above 2.66 Pa, the growth was epitaxial with the [111] direction perpendicular to the substrate. The epitaxial relation and crystal quality were evaluated by using high-resolution X-ray diffraction, which showed distinct pendellösung oscillations in θ–2θ scan of the ITO(222) reflection. The in-plane orientation relationship, ITO [33̄0]//Al2O3 [5̄501] and ITO [1̄/4,3̄/4,1]//Al2O3 [0001], was identified by X-ray φ scan, where no other domains with different orientations could be detected. Good values of mobility, N30 cm/Vs, and resistivity, ∼2×10 Ω cm, were measured by the Hall and van der Pauw methods at room temperature. © 2007 Elsevier B.V. All rights reserved.