Photoluminescence from low temperature grown InAs∕GaAs quantum dots

Abstract

The authors investigated a set of self-assembled InAs∕GaAs quantum dots (QDs) formed by molecular beam epitaxy at low temperature (LT, 250°C) and postgrowth annealing. A QD photoluminescence (PL) peak around 1.01eV was observed. The PL efficiency quickly quenches between 6 and 40K due to the tunneling out of the QD into traps within the GaAs barrier. The PL efficiency increases by a factor of 45–280 when exciting below the GaAs band gap, directly into the InAs QD layer. This points towards good optical quality QDs, which are embedded in a LT-GaAs barrier with a high trapping efficiency.