Well-AlignedIrO2Nanocrystals

We review the results of synthesis of well-aligned IrO2 nanocrystals (NCs) on sapphire (SA), LiNbO3 (LNO), LiTaO3 (LTO) substrates via reactive magnetron sputtering and metal-organicchemical vapor deposition. The surface morphology and structural properties of the as-deposited NCs were characterized. Field emission scanning electron microscopy micrographs reveal that NCs grown on SA(100)/LNO(100) are vertically aligned, while the NCs on SA(012)/LTO(012) and SA(110) contain singly and doubly tilted alignments, respectively, with a tilt angle of ∼35∘ from the normal to the substrates. NCs grown on SA(001) show in-plane alignment with mosaic structure. The X-ray diffraction results indicate that the NCs are (001), (101), and (100) oriented on SA(100)/LNO(100), SA(012)/LTO(012)/SA(110), and SA(001) substrates, respectively. A strong substrate effect on the alignment of the IrO2 NCs deposition has been demonstrated. The roles of different substrates in the formation of various textures of nanocrystalline IrO2 are studied and the possible mechanisms have been discussed