Effect of a wide range of Mn concentration on structural, electrical and optical properties of SnO2 transparent semiconducting films

In this work, tin oxide thin films alloyed with manganese up to 60 at.% were deposited by spray pyrolysis route, and the effect of Mn on the structural, optical, electrical and thermo-electrical properties of the films was investigated. The results show that all the deposited films are polycrystalline with tetragonal rutile structure. The solubility limit of Mn in SnO2 sprayed films was found to be about 15 at.%. The lattice volume of SnO2:Mn films turned out to be minimum at the critical Mn concentration of 15% implying that two different mechanisms should work for Mn addition: For low Mn concentration (< 15%) substitutional doping is the working mechanism, while for more Mn concentration, interstitial doping is predominant in the involved films. Mn addition in SnO2 films varied their crystallite size, transparency, band-gap, resistivity and carrier concentration. The most striking effect of Mn addition was revealed as getting p-type conductivity in SnO2:Mn films with Mn concentration in the range of 15-40%.