Charge transfer in semi-insulating Fe-doped GaN

Academic Article

Abstract

  • Charge transfer kinetics is studied in free-standing Fe-doped GaN using photo-induced electron paramagnetic resonance (EPR). Samples with Fe concentrations of 10 17 cm -3 reveal an increase in Fe 3 during exposure with photon energy greater than 0.8 eV, while samples with higher Fe concentrations exhibit a decrease in the Fe 3 under the same conditions. Steady-state photo-EPR measurements of the most lightly doped sample imply the existence of an Fe 2/3 defect level within 0.8 eV of the conduction band edge consistent with earlier work, but time-dependent measurements of more heavily doped crystals indicate a multi-step charge transfer process. Analysis of time-dependent photo-EPR data reveals that charge exchange may be separated into two processes, one that is temperature independent and one that depends monotonically on temperature. While a physical model for the charge transfer is not apparent, likely scenarios involve charge trapping at extended defects and phonon interactions. © 2012 American Institute of Physics.
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    Author List

  • Dashdorj J; Zvanut ME; Harrison JG; Udwary K; Paskova T
  • Volume

  • 112
  • Issue

  • 1