No abstract

We have measured the thermally stimulated current from self-organized InAs quantum dots grown by molecular-beam epitaxy. The glow curve exhibits peaks at 43, 82, and 127 K with accompanying attenuated current oscillations at 107 K. Based on the excitation energy above and below the GaAs band gap, the oscillations are ascribed to AsGa-related point defects in the conduction GaAs matrix. By comparing with the photoluminescence and photoconductivity measurements, we conclude that the peaks at 82 and 43 K arise from the electron trapping in the InAs quantum dots. We point out that the technique of thermally stimulated current provides a simple alternative method to obtain the energy levels in self-organized quantum-dot systems.