Analysis of critical doping level of sprayed antimony doped tin oxide films

Antimony doped tin oxide films are fabricated using a simplified and inexpensive spray pyrolysis technique. The variation in the sheet resistance, as a function of Sb/Sn ratio in the spraying solution, is studied. The sheet resistance decreases with the increase in doping level, attains a minimum at a particular doping level and increases with further doping. This critical value of the doping ratio (Sb/Sncritical), at which the transition takes place, is found to be 2.5 at.%, when the concentration of the precursor solution is 0.8 M and 4.5 at.% when the concentration is 0.4 M. The reason for this variation is analyzed with the support of the Sb/Sncritical values, obtained by various researchers. This Sb/Sncritical is found to depend mainly on the carrier concentration of the films.