Characterization of electron trap states due to InAs quantum dots in GaAs

Abstract

InAs quantum dots grown in a GaAs matrix are investigated using capacitive transient spectroscopy and transmission electron microscopy (TEM). Two deep levels are detected which are energetically too deep to be the intrinsic electron levels of the quantum dots. Both TEM as well as the detailed non-exponential behavior of the electron capture indicate that the traps do not result from dislocations in the GaAs matrix. We propose that the measured trap levels are due to point defects in or near the quantum dots.