The Prepration of p-Type Transparant Conducting Oxides CuCr1-xCaxO2 and Research about Its Electrical and Optical Property

Transparant conducting oxides showing the combination of high electrical conductivity and high transparency for visible light have been based on electron doping into a conduction band. For p-type delafossite oxides，the valence band is commonly the oxygen 2p band. Doping to produce holes in this band but the electronic conductivity of such p-type oxides is highly activated and can generally only be measured at temperatures well above room temperature. So it is very desirable to improve conductivity by doping wide-gap delafossites as transparant conducting oxides nowadays. The article reported the prepration and characterization of Ca-doped CuCrO2 monophasic delafossites. It was found that conductivity had a notable improvement after Ca-doped and reached 3. 2×10-2 S/cm for x=0.06 Ca-doped at room temperature and the structures had not been changed. The temperature dependence of electrical conductivity around room temperture was consistent with thermal activation type very well from 200 K to 300 K. The activation energe was 0. 36 eV before doping，but it changed to 0.27 eV when Ca-doped. This phenomenon suggest that in pure non-doped CuCrO2，carrier was the Cu+ d. After Ca-doped，the Cu2+ was formed from the Cu+ by a charge compensating process when the divalent Ca2+ substituted for the trivalent Cr3+ . The Seebeck coefficients being large positive constants implied that all the samples were p-type conducting oxides.