Photocurrent in self-organized InAs quantum dots in 1.3 μm InAs/InGaAs/GaAs semiconductor laser heterostructures

The photocurrent spectra of InAs/InGaAs/GaAs laser heterostructures with self-organized InAs quantum dots (QDs) are studied. The study has been performed with a sample illuminated perpendicularly or in parallel to the QD plane. The optical density of QDs, maximum gain in the laser structure, radiative recombination time, and polarization characteristics of absorption have been determined from the experiment. The photocurrent spectra were correlated with specific features of lasing. The absorption spectrum is interpreted as a superposition of optical transitions between states of the discrete energy spectrum, those between the states of the continuous spectrum, and “mixed” transitions.