Microstructure and properties of annealed IrO2 thin films prepared by pulsed laser deposition

Iridium oxide (IrO2) thin films were prepared on Si (1 0 0) and quartz glass substrates by pulsed laser deposition (PLD) technique. Electrical and optical properties, as well as morphology of annealed IrO2 thin films in air ambient were investigated by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), four-point probe method, and ultraviolet-visible spectrometer. The results showed that the surface morphology of IrO2 thin films became denser and compact after being annealed at 600–800 °C for 30 min, while the surface roughness changed little. The room-temperature electrical resistivity of IrO2 films slightly decreased after being annealed at 600–750 °C and showed a minimum electrical resistivity of (38 ± 3) μΩ cm at 750 °C. The average transmittance of annealed IrO2 thin films (thickness: 65 nm) in the visible range was increased to almost 85–88%.