Structural, Optical and Electrical Properties of Sn-doped Zinc Oxide Transparent Films Interesting for Organic Solar Cells (OSCs)

Tin doped zinc oxide films were prepared on glass substrates by spray pyrolysis. The effect of Sn content on microstructures and optoelectronic properties of the films were investigated by X-ray diffraction, UV-visible spectrophotometer and Hall effect. The results show that all the films are polycrystalline with (002) plane is preferential orientation. The Sn content significantly affects the microstructure and optoelectronic properties of the films. The film with Sn dopant of 1% has the largest grain size of 62 nm, the highest average visible transmittance of 85%. The electrical studies show degenerate, n-type semiconductor nature with minimum resistivity of 2.60 10-2 Ω cm. Furthermore, the optical band gaps were determined by the Tauc's law and observed to be an increasing tendency with the incorporation of the Sn content. The blue shift with dopant concentration of the absorption edge can be described by the Moss-Burstein effect. The highest figure of merit observed in the present study is 2.24 10-4 Ω-1. Our results suggest the potential application of Sn doped ZnO thin film as transparent conducting oxide layer for different optoelectronic and photovoltaic devices.