Electrical doping of gas-sensitive, semiconducting Ga2O3 thin films

Recently polycrystalline n-type semiconducting Ga2O3 thin films have been characterized as a new sensor base material for high-temperature gas sensors. The influences of donator type and acceptor type dopants on the overall conductivity and its gas-sensitivity of Ga2O3 thin films are investigated. It was found that the change in conductivity of the polycrystalline thin films is significantly smaller than in the case of single crystals reported in the literature. However, a difference in overall conductivity of two orders of magnitude have been found between acceptor and donor doped specimens. There is no effect of the dopants on the bulk controlled oxygen sensitivity. In contrast, a strong influence of the dopants on the surface controlled sensitivity to reducing gases was found. The results are explained by a model.