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

Abstract: Indium tin oxide (ITO) thin films were grown on the (112¯0) 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 [33¯0]//Al2O3 [5¯501] and ITO [1¯/4,3¯/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, >30 cm2/Vs, and resistivity, ∼2×10−4 Ω cm, were measured by the Hall and van der Pauw methods at room temperature. [Copyright &y& Elsevier]