Identification of trap states for two-step two-photon-absorption processes in InAs quantum structures for intermediate-band solar cells

Intermediate bands bear trap and recombination centers for carriers generated in other energy levels. Assessment of recombination centers is important for achieving efficient carrier generation. We measure the photocurrent (PC) originating from InAs quantum structures embedded in an undoped (Al)GaAs matrix due to excitation with multiple tunable beams. With an infrared light excitation the influence of trapping or recombination on the quantum dot PC generation efficiency via two-step two-photon-absorption processes is evaluated.