The Study of ZnO/Cu2O heterojunction prepared by Sputtering method

[[abstract]]氧化亞銅(Cu2O)/氧化鋅(ZnO)異質接面太陽能電池已經被廣泛的研究，目前最高的效率為約4%，是使用熱氧化法生長氧化亞銅。在過去的研究提到利用磁控濺鍍系統在氧化亞銅上沉積氧化鋅可能會有部分的氧化亞銅被還原成銅或是在有氧離子環境下被氧化為氧化銅。 因此，我們藉由磁控濺鍍系統來研究有關接面特性的影響，我們在氧化亞銅與氧化鋅中間沉積一層過渡層氧化銅(CuO)/鋅(ZnOx)並且與未沉積過度層之氧化亞銅(Cu2O)/氧化鋅(ZnO)比較。藉由氧化銅(CuO)/鋅(ZnOx)做為過渡層再利用熱氧化還原將接面氧化還原為氧化亞銅(Cu2O)/氧化鋅(ZnO)，藉由此方法改善接面。接著藉由電流-電壓曲線(I-V)，電容-電壓曲線(C-V)，X光繞射儀(X-ray diffraction, XRD)、二次離子質譜儀(Secondary ion mass spectroscopy, SIMS)以及霍爾(Hall measurement)來量測p-n接面特性。分別計算出p-n接面只有單沉積氧化亞銅與氧化鋅以及由過渡層熱氧化還原氧化銅與氧化鋅的理想因子(ideal factor)，飽和暗電流(saturation dark current) 和內建電位(build-in voltage)，並由電流-電壓曲(I-V)線觀察起始電壓，利用霍爾量測薄膜載子濃動及遷移率，XRD觀察薄膜結晶方向以及SIMS分析縱深薄膜組成。由結果指出只有單沉積氧化亞銅與氧化鋅以及由過渡層熱氧化還原氧化銅與氧化鋅，其理想因子分別為2.9及3.38。[[abstract]]Cu2O/ZnO heterojunction solar cell has been extensively studied, the highest efficiency using the thermal oxidation Cu2O substrate up to now is about 4%.?It have been known that part of the Cu2O could be?reduced to metalic Cu or oxided to CuO due to the preferential oxygen plasma during the magnetron sputtering deposition of ZnO on Cu2O. Therefore, we have adopted an intermediate layer of CuO/ZnOx between the Cu2O and ZnO layers deposited by magnetron sputtering to study the influence on the junction properties, which are compared to those in the as-deposited Cu2O/ZnO junction, the CuO/ZnOx juction as a buffer layer and using thermal redox formation of Cu2O / ZnO to improve device junction by this method. The properties of p-n heterojunctions have been characterized by measuring the current-voltage(I-V), capacitance-voltage(C-V), Secondary ione mass spectroscopy(SIMS),?X-ray diffraction(XRD) and Hall measurement. The ideality factor, saturation dark current and build-in voltage of p-Cu2O/n-ZnO heterojunctions of the as-deposited samples and the thermal annealing samples with CuO/ZnOx intermediate layer are calculated and formed by I-V curve observe the turn-on voltage, using Hall measurement thin film carrier concentration and mobility, XRD(x-ray diffraction) observation of thin film crystalline direction, and also the use of SIMS analysis thin film high depth resolution composition. The ideality factors of the as-deposited sample and thermal annealing sample with intermediate layer are 3.38 and 2.9, respectively