Simulation of electron escape from GaNAs/GaAs quantum well solar cells

Quantum wells embedded in the active region of single-bandgap solar cells have previously been shown to increase the absorption of photons of energies lower than the host bandgap, while maintaining the open-circuit voltage. Fast carrier escape from the quantum wells is essential to achieve such performance enhancements. In the present work, we use ensemble Monte Carlo simulation to model the escape time for photo-excited carriers in dilute nitride GaNAs/GaAs quantum wells to the continuum, for different well structures. The simulated electron escape rate due to polar optical phonon absorption and emission decreases exponentially with the well depth in agreement with thermionic emission theory.