Role of Insertion Layer Controlling Wavelength in InGaAs Quantum Dots

Abstract

We have observed the red shift of the emission wavelength in InGaAs/GaAs quantum dots by employing a very thin AlGaAs insertion layer (IL). The thin AlGaAs layer of less than 10 nm in thickness was inserted immediately after the formation of self-assembled InGaAs quantum dots (QDs) on a GaAs buffer layer. The low temperature (15 K) photoluminescence peak typically appears at around 1.1 µm in the sample without IL whereas it is red-shifted up to 1.25 µm as the IL thickness increases. It is interpreted that the thin AlGaAs IL releases the local strain around QDs asymmetrically.