Electrical Characteristics and Nanocrystalline Formation of Sprayed Iridium Oxide Thin Films

摘要

Nanostructure and electrical properties of iridium oxide (IrO_2) thin films prepared by spray pyrolysis technique (SPT) have been experimentally characterized. The effect of solution molarity (SM) and substrate temperature (T_(sub)) on the nanostructure features and electrical conductivity of these films has been investigated. The results of X-ray diffraction (XRD) showed that all samples prepared at T_(sub) = 350℃ with different SM, IrO_2 appear almost in amorphous form. XRD revealed that the films deposited at T_(sub) = 450℃ were tetragonal structures with a preferential orientation along (101) direction.Moreover, the degree of crystallinity was improved by solution molarity. Single order Voigt profile method has been used to determine the nanostructure parameters at different SM and T_(sub). The dark conductivity measurements at room temperature as a function of SM were observed and the value of conductivity were slightly increases at higher SM, reaching the bulk value of 20 Ω~(-1)cm~(-1). The values of activation energy of ΔE and σo of IrO_2 were found to be 0.21 eV and 1.68 × 10~(-3)Ω~(-1) · cm~(-1), respectively.