Thermal instability of electron traps in InAs/GaAs quantum dot structures

Deep level transient spectroscopy (DLTS) in temperature and frequency scanned modes has been used to characterize deep-level defects present in samples with InAs/GaAs quantum dots (QDs). Two deep energy traps have been studied in details, a trap with thermal activation energy at 1.03 eV, which has no correspondence to DLTS data in the literature to make any comparison and an accompanied trap at 0.79 eV belonging to EL2 family. The concentration of the 1.03 eV trap exhibited significant changes with temperature, whereas the trap at 0.79 eV was stable on a reduced level. The results for the 1.03 eV trap are discussed in terms of a metastable double-oscillator.