Carrier injection in GaAsP(N)/GaPN Quantum Wells on Silicon
Résumé
We report efficient carrier injection in GaAsPN/GaPN quantum wells grown on Si. Electroluminescence of GaAsPN/GaPN and GaAsP/GaP quantum wells is first presented. Nitrogen is found to induce large bandgap bowing in the bandstructure as well as spectacular enhancement of radiative quantum efficiency. Tight-binding bandstructure calculations are then presented which reveal N-induced large bandgap modification. N-localised levels are supposed to play significant role in carrier injection inside GaAsPN/GaPN quantum wells while disorder alloying effects also participate to the achievement of such a high quantum efficiency. GaAsP/GaP and GaAsPN/GaPN quantum wells are finally grown on Silicon substrate, very near the GaP/Si interface. High resolution transmision electron microscopy performed on GaAsP/GaP/Si quantum wells indicate good strain status, as well as GaP/Si interface originating defects. Photoluminescence is finally detected at 810 nm up to 230K on silicon substrate from GaAsPN/GaPN quantum wells. This is explained by both a better carrier injection efficiency related to N-localized energy levels as well as a higher quantum efficiency than GaAsP/GaP/Si quantum wells.