Ultrafast carrier capture and relaxation in InGaAs self-organized quantum dots

Summary form only given.The study of carrier capture and relaxation in self-organized quantum dots is a key step in the understanding of the device physics of novel quantum-dot lasers and detectors. We have investigated these ultrafast processes in In/sub 0.4/Ga/sub 0.6/As quantum dots using femtosecond differential transmission (DT) spectroscopy at 10 K. The sample consists of four undoped layers of self-organized InGaAs quantum dots with GaAs barriers and AlGaAs cladding layers. The band-structure calculations of the dots obtained with an eight-band k.p model show two confined states in the conduction band and many levels in the valence band.