Enchanced 1.3-μm-emission from InAs quantum dots embedded in symmetric (In,Ga)As quantum-well structures

摘要

We have optically characterized the emission of a layer of InAs quantum dots embedded at the center of symmetric (In,Ga)As quantum-well structures. By grading the profile of the indium composition in the quantum-well regions in a certain way, it is found that the room-temperature emission of the dots can be enhanced by almost an order of magnitude compared to dots bounded by conventional (In,Ga)As quantum wells. The largest enhancement is obtained for structures where the grading is achieved by using a GaAs/InAs superlattice structure to form a quasi-linear distribution of the indium. The dots inside the graded quantum-well structures are engineered to emit at the important telecommunication wavelength of 1.3 μm.