The thickness dependence of crystal structure and electrical properties is studied for rutile-type RuO2 (100) thin films. The island growth mode results in a monotonically varying lattice strain along the a-axis from negative to positive with increasing thickness. Decrease in the thickness below 20 nm increases the resistivity drastically, resulting in insulating-like behaviors. The metallic behaviors of the thicker films are well explained by the modified Bloch–Grüneisen function as in bulk RuO2, where the strain has a significant influence on the conduction parameters. The insulating-like behaviors of the thinner films are assigned to 2D localization and Mott variable range hopping, reflecting the effects of the size and growth mode on electrical conduction.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics