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An elegant verification of the negative charge-state of the DX centre from mobility measurements of 2D electrons

Research output: Contribution to journalJournal article


  • M Hayne
  • Alan Usher
  • Jeffrey J Harris
  • C Thomas Foxon
<mark>Journal publication date</mark>1996
<mark>Journal</mark>Surface Science
Issue number1-3
Number of pages5
Pages (from-to)574-578
<mark>Original language</mark>English


We have measured the persistent changes in the mobility and density of the two-dimensional electron system in two modulation-doped GaAs/AlxGa1-xAs single heterojunctions at 0.3 K following illumination with an infrared light-emitting diode. One sample behaves conventionally, with an immediate increase in both density and mobility when illuminated. However, the second sample shows remarkable different behaviour, with no change in density for more than 20% of the total time taken to reach the maximum density, and an increase in mobility of more than 10% in this initial illumination period. We demonstrate that these results provide very simple and convincing evidence for the negative-charge state of the DX centre.