Room-temperature 1.6 µm light emission from InAs/GaAs quantum dots with a thin GaAsSb cap layer
It is demonstrated that the emission of InAs quantum dots (QDs) capped with GaAsSb can be extended from 1.28 to 1.6 µm by increasing the Sb composition of the capping layer from 14% to 26%. Photoluminescence excitation spectroscopy is applied to investigate the nature of this large redshift. The dominant mechanism is shown to be the formation of a type-II transition between an electron state in the InAs QDs and a hole state in the GaAsSb capping layer. The prospects for using these structures to fabricate 1.55 µm injection lasers are discussed. ; This work is supported by the U.K. Engineering and Physical Sciences Research Council (EPSRC) (Grant No.GR/S49308/01) and the European Union Network of Excellence "SANDiE" (Contract No. 500101). ; Peer reviewed