Studies on Cu, Fe, and Mn Doped SnO2 Semi-Conducting Transparent Films Prepared by a Vapour Deposition Technique

Jochan Joseph ； Varghese Mathew ； K. E. Abraham

《Chinese Journal of Physics》 45卷1期 (2007/02) Pp. 84-97

並列摘要

SnO2 is a wide band gap n-type semi-conductor that has a wide range of applications. Cu, Fe, and Mn doped SnO2 semi-conducting transparent thin films were prepared by a simple vapour deposition technique under different deposition parameters. The structural, photo-electronic, optical, and electrical properties of the doped and undoped SnO2 films were studied. The x-ray diffraction studies show the crystalline nature of the films having preferential orientation along the (101), (211), and (301) planes with an average grain size of 100 Å. Photoconductivity and phototvoltaic effects of SnO2 Films were also studied. The optical properties of the films were studied by measuring their optical transmission as a function of wavelength. The optical transmission is found to be increased on doping, particularly with a remarkable increase on Mn doping. The band gap, refractive index, and thickness of the films were calculated from the films were calculated from the ultra-violet transmittance and absorption graphs. The optical band gap of undoped film is found to be 4.08 eV. On doping it shifts to lower energies and then increases on increasing the concentration of the dopants. Its electrical properties were determined by the four probe, Van der Pauw, and Hall probe methods. Resistivity decreases on Cu and Fe doping but increases on Mn doping. The minimum resistivity for the doped SnO2 films was found to be 0.381×10^(-4)Ωm which is deposited at 575℃ with 3 wt% of Fe doping.