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[16p-A304-12] Reduction in resistivity of Cu3N and Cu2O thin films by O2-annealing
Keywords:semiconductor, thin film, solar cell
Typical MOCVD-deposited CuO thin films have high resistivity and no clear p-type conduction. which can be turned into having p-type and lower resistivity by O2 annealing. However, their resistivity is still as high as 102-103 Ω・cm, which we believe is due to low oxidation rate from XPS results. For improving oxidation rates, we focused on 2 precursors, sputtered-Cu3N and MOCVD-Cu2O. In this study, CuO thin films were prepared by O2 annealing both films (500°C, 30 min, hereafter CuO(Cu3N) and CuO(Cu2O), respectively) and compared, including a O2-annealed MOCVD-deposited CuO thin film (CuO). Thermoelectromotive force measurements showed that the high-temperature side electrode was negative in both cases, indicating p-type conduction. CuO(Cu3N) was the largest in absolute voltage. From the I-V measurements between In dots formed on the surface, CuO(Cu3N) showed the lowest resistance, while CuO(Cu2O) was comparable to O2-annealed CuO thin films. In the activation energy determined from the Arrhenius plot of the resistance from RT to 200°C, all samples showed in the range of 110-130 meV , indicating that the each carrier source is considered to be the same.