Investigation of room temperature non-linear sub-bandgap photocurrent generation in InAs/GaAs quantum dot solar cells

We present the first observation at room temperature of the nonlinear sub-bandgap photocurrent generation in an InAs/GaAs quantum dots solar cell via the extended tailing distribution of states and the quantum dot confined sates. The two-photon absorption (2PA) photocurrent generation is evaluated. The saturation intensity of the quantum dot ground state transition is measured experimentally and theoretically explained in terms of a saturation of an inhomogeneous broadened transition.