Thermal emission of electrons from selected s-shell configurations in InAs/GaAs quantum dots

The thermal emission of electrons from self-assembled InAs/GaAs quantum dots, prepared by molecular-beam epitaxy, with an average base/height size of 20 nm/11 nm in Schottky diodes has been investigated using deep level transient spectroscopy (DLTS). By applying an appropriate set of voltage pulses across the Schottky diode, the two different s-electron configurations have been investigated separately. This avoids the problem of interference between overlapping peaks in DLTS data. We find that a difference in activation energy for the thermal electron emission between the two configurations agrees with expected variation in electron energy levels due to the size distribution of the quantum dots. (C) 2003 American Institute of Physics.