Imaging ambipolar diffusion of photocarriers in GaAs thin films

Abstract

Images of the steady-state luminescence of passivated GaAs self-standing films under excitation by a tightly-focussed laser are analyzed as a function of light excitation power. While unipolar diffusion of photoelectrons is dominant at very low light excitation power, an increased power results in a decrease of the diffusion constant near the center of the image due to the onset of ambipolar diffusion. The results are in agreement with a numerical solution of the diffusion equations and with a physical analysis of the luminescence intensity at the centre of the image, which permits the determination of the ambipolar diffusion constant as a function of electron concentration.

5 figures

References in corpus (4)

• Ambipolar diffusion of photo-excited carriers in bulk GaAs
• Ambipolar spin diffusion and D'yakonov-Perel' spin relaxation in GaAs quantum wells
• Imaging charge and spin diffusion of minority carriers in GaAs
• Temperature dependence of ambipolar diffusion in silicon-on-insulator

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• Rapid diffusion of electrons in GaMnAs
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• Anomalous ambipolar transport in depleted GaAs nanowires
• Charge and spin transport over record distances in GaAs metallic n-type nanowires : II nonlinear charge transport
• Charge and spin transport over record distances in GaAs metallic n-type nanowires : I photocarrier transport in a dense Fermi sea