Photoluminescence of InAs quantum dots coupled to a two-dimensional electron gas

Self-assembled InAs quantum dots have been extensively studied by a variety of experimental techniques. Works have been done on the transport properti es of the InAs dots located near a two-dimensional electron gas (2DEG). How ever, there have been few reports on the optical properties of the InAs dot s located closely to 2DEG. In this work, InAs dots samples with 2DEG and wi thout 2DEG grown by solid source molecular beam epitaxy were studied using photoluminescence measurements. Different photoluminescence behaviors betwe en the InAs dots and the InAs dots near the 2DEG were observed. It was foun d that the emission efficiency of the InAs dots was significantly enhanced by the existence of the nearby 2DEG and the thermal activation energy of th e InAs dots was decreased by the 2DEG. It was speculated that the 2DEG at t he AlGaAs/GaAs interface worked as an electron reservoir to the InAs dots. As a result, the conduction band between the dots and 2DEG is lowered, and thus the thermal activation energy of PL is lowered. It was concluded that in this way the optical properties of the InAs quantum dots could be tailor ed for optical applications.