Nitrogen-doped transparent tin oxide thin films deposited by sputtering

Nitrogen-doped tin oxide thin films prepared by reactive rf magnetron sputtering have been investigated to examine their structural, electrical, and optical properties. Of particular interest was whether the nitrogen doping could create defect levels in tin oxide and change the electrical characteristics of tin oxide. Various N2/O2/Ar gas contents were evaluated, and the thin films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis spectrometer, and Hall effect measurements. With nitrogen incorporation in tin oxide, electrical conductivity as high as 134.2 (Ω cm)−1 was achieved due to an increase in carrier concentration. The optical absorption edge moved to a shorter wavelength as the nitrogen content was increased. The XRD and XPS results indicate that the small amount of substitution nitrogen created the second type of defect in addition to oxygen deficiencies and tin interstitials.