Structure of NiO and Li-doped NiO single crystalline thin layers with atomically flat surface

Crystalline thin films of NiO and nominally 20 at.% Li-doped NiO were deposited at room temperature by pulsed laser deposition on the lattice matched MgO (100) substrate. As-deposited films were annealed at various temperatures to promote a solid phase epitaxial growth and control the surface morphology. Films were characterized by AFM and RHEED measurements. AFM images of the NiO film annealed at 1200 °C for 30 min showed an atomically flat surface and an excellent step-terrace morphology with a step height corresponding to one unit cell of NiO over a wide range of 2 μm×2 μm. Formation of atomically smooth surface in a range of annealing temperatures is highlighted and a temperature of 1200 °C is identified as being the most suitable in the solid phase epitaxy for single crystalline growth and a smooth surface of the films deposited by PLD.