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Title: Oxygen related recombination defects in Ta{sub 3}N{sub 5} water splitting photoanode

A key route to improving the performance of Ta{sub 3}N{sub 5} photoelectrochemical film devices in solar driving water splitting to hydrogen is to understand the nature of the serious recombination of photo-generated carriers. Here, by using the temperature-dependent photoluminescence (PL) spectrum, we confirmed that for the Ta{sub 3}N{sub 5} films prepared by nitriding Ta{sub 2}O{sub 5} precursor, one PL peak at 561 nm originates from deep-level defects recombination of the oxygen-enriched Ta{sub 3}N{sub 5} phases, and another one at 580 nm can be assigned to band recombination of Ta{sub 3}N{sub 5} itself. Both of the two bulk recombination processes may decrease the photoelectrochemical performance of Ta{sub 3}N{sub 5}. It was difficult to remove the oxygen-enriched impurities in Ta{sub 3}N{sub 5} films by increasing the nitriding temperatures due to their high thermodynamically stability. In addition, a broadening PL peak between 600 and 850 nm resulting from oxygen related surface defects was observed by the low-temperature PL measurement, which may induce the surface recombination of photo-generated carriers and can be removed by increasing the nitridation temperature. Our results provided direct experimental evidence to understand the effect of oxygen-related crystal defects in Ta{sub 3}N{sub 5} films on its photoelectric performance.
Authors:
; ;  [1] ;  [2] ;  [2] ;  [1] ;  [2] ;  [2] ;  [2]
  1. National Laboratory of Solid State Microstructures and Ecomaterials and Renewable Energy Research Center (ERERC) at Department of Physics, Nanjing University, Nanjing 210093 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22485962
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARRIERS; CRYSTAL DEFECTS; FILMS; HYDROGEN; IMPURITIES; NITRIDATION; OXYGEN; PERFORMANCE; PHOTOLUMINESCENCE; PRECURSOR; RECOMBINATION; SPECTRA; STABILITY; TANTALUM NITRIDES; TANTALUM OXIDES; TEMPERATURE DEPENDENCE; WATER