Effect of coadsorption of reducing gases on the conductivity of β-Ga2O3 thin film in the presence of O2

The electrical conductivity of sputtered 2 μm thick films of the oxide semiconductor β-Ga2O3 was studied in function of the partial pressure of CO or H2 above the solid and also in the presence of CO+O2, H2+O2 and CO+H2 mixtures. The concentrations of the examined gases varied in the range 0.01-1 vol.% in nitrogen carrier gas, while the experiments were carried out at 823, 873 and 923 K. Under the influence of H2 and CO the conductivity of the samples increased with the partial pressures of the gases according to the relations: lg σ (1/n)lgPco and lgσ(1/m)lgPH(2),where n and m are greater than unity. As a second step the effect of the coadsorption of CO+O2 and H2PLUO2 on the conductivity was investigated.