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Title: Photovoltaic effect in an indium-tin-oxide/ZnO/BiFeO{sub 3}/Pt heterostructure

We have studied the photovoltaic effect in a metal/semiconductor/ferroelectric/metal heterostructure of In{sub 2}O{sub 3}-SnO{sub 2}/ZnO/BiFeO{sub 3}/Pt (ITO/ZnO/BFO/Pt) multilayer thin films. The heterolayered structure shows a short-circuit current density (J{sub sc}) of 340 μA/cm{sup 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{sup +}-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.
Authors:
 [1] ;  [2] ;  [3] ;  [1]
  1. Department of Materials Science and Engineering, National University of Singapore (Singapore)
  2. (Agency for Science, Technology, and Research) (Singapore)
  3. Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research) (Singapore)
Publication Date:
OSTI Identifier:
22350969
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BISMUTH COMPOUNDS; CURRENT DENSITY; ELECTRIC CONTACTS; ENERGY CONVERSION; EXCITATION; FERRITES; FERROELECTRIC MATERIALS; INDIUM OXIDES; LAYERS; MONOCHROMATIC RADIATION; PHOTOELECTRON SPECTROSCOPY; PHOTOVOLTAIC EFFECT; PLATINUM; SCHOTTKY BARRIER DIODES; SEMICONDUCTOR JUNCTIONS; SEMICONDUCTOR MATERIALS; THIN FILMS; TIN ADDITIONS; ULTRAVIOLET RADIATION; ZINC OXIDES