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Title: Effect of Fe-doping on nonlinear optical responses and carrier trapping dynamics in GaN single crystals

We presented a quantitative study on the Fe-doping concentration dependence of optical nonlinearities and ultrafast carrier dynamics in Fe-doped GaN (GaN:Fe) single crystals using picosecond Z-scan and femtosecond pump-probe with phase object techniques under two-photon excitation. In contrast to the two-photon absorption that was found to be independent on the Fe-doping, the nonlinear refraction decreased with the Fe concentration due to the fast carrier trapping effect of Fe{sup 3+}/Fe{sup 2+} deep acceptors, which simultaneously acted as an efficient non-radiative recombination channels for excess carriers. Remarkably, compared to that of Si-doped GaN bulk crystal, the free-carrier refraction effect in GaN:Fe crystals was found to be enhanced considerably since Fe-doping and the effective carrier lifetime (∼10 ps) could be tuned over three orders of magnitude at high Fe-doping level of 1 × 10{sup 19 }cm{sup −3}.
Authors:
; ; ;  [1] ; ;  [2] ;  [1] ;  [3]
  1. College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China)
  2. Department of Physics, Harbin Institute of Technology, Harbin 150001 (China)
  3. (China)
Publication Date:
OSTI Identifier:
22489051
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 5; 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; CARRIER LIFETIME; CARRIERS; DOPED MATERIALS; GALLIUM NITRIDES; IRON IONS; MONOCRYSTALS; NONLINEAR PROBLEMS; PHOTONS; TRAPPING