Photovoltaic effect in an indium-tin-oxide/ZnO/BiFeO3/Pt heterostructure
Photovoltaic effect in an indium-tin-oxide/ZnO/BiFeO3/Pt heterostructure
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DOI：
10.1063/1.4899146
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发表时间：
2014-10-20
影响因子：
4
通讯作者：
Wang, John
中科院分区：
文献类型：
--
作者：
Fan, Zhen;Yao, Kui;Wang, John
我们研究了In2O3-SnO2/ZnO/BiFeO3/Pt (ITO/ZnO/BFO/Pt)多层薄膜的金属/半导体/铁电/金属异质结构中的光伏效应。该异质层结构在蓝色单色照明下显示出340μA/cm(2)的短路电流密度(J(sc))和高达0.33%的能量转换效率。阐明了光伏机制，特别是光激发电子-空穴（e-h）对的主要产生位点以及e-h对分离的驱动力。与 ITO/BFO/Pt 相比，ITO/ZnO/BFO/Pt 的光电流显着增加，这归因于 ZnO 产生丰富的 e-h 对。紫外光电子能谱揭示了 ITO/ZnO/BFO/Pt 的能带排列，其中 BFO/Pt 和 ZnO/BFO 界面分别形成肖特基势垒和 n(+)-n 结。因此，在两个界面处形成的两个内置场建设性地负责光激发e-h对的分离和传输。 (C) 2014 AIP 出版有限责任公司。
We have studied the photovoltaic effect in a metal/semiconductor/ferroelectric/metal heterostructure of In2O3-SnO2/ZnO/BiFeO3/Pt (ITO/ZnO/BFO/Pt) multilayer thin films. The heterolayered structure shows a short-circuit current density (J(sc)) of 340 mu A/cm(2) and an energy conversion efficiency of up to 0.33% under blue monochromatic illumination. The photovoltaic mechanism, specifically in terms of the major generation site of photo-excited electron-hole (e-h) pairs and the driving forces for the separation of e-h pairs, is clarified. The significant increase in photocurrent of the ITO/ZnO/BFO/Pt compared to that of ITO/BFO/Pt is attributed to the abundant e-h pairs generated from ZnO. Ultraviolet photoelectron spectroscopy reveals the energy band alignment of ITO/ZnO/BFO/Pt, where a Schottky barrier and an n(+)-n junction are formed at the BFO/Pt and ZnO/BFO interfaces, respectively. Therefore, two built-in fields developed at the two interfaces are constructively responsible for the separation and transport of photo-excited e-h pairs. (C) 2014 AIP Publishing LLC.