Effect of Ruthenium Concentration on Structural and I-V Characteristics of ZnO Thin Films by Sol-Gel Method

Nanocrystalline ruthenium (Ru)-doped ZnO thin films on sapphire substrate was prepared using sol-gel method by spin coating technique. The structural and I-V characteristics of Ru doped ZnO thin films were studied from the X-ray di r raction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) analysis and Raman spectroscopy. X-ray di r raction (XRD) results revealed that the deposited films belonged to hexagonal wurtzite structure with c-axis orientation. It is also con firmed from the Raman spectra. Enhancement of longitudinal optical (LO) phonon is observed by the strong electron-phonon interaction. An observed increment in sheet resistance with increase in dopant percentage of Ru (1-2 mol%) in ZnO films was found and better I-V characteristic behavior was observed at 1 mol% of Ru-doped ZnO thin films. Trap limited current flow inside the material was calculated from the log I versus log V plot in the higher voltage region.