Photoreflectance and photoluminescence investigations of a step-like GaInNAsSb/GaAsN/GaAs quantum well tailored at 1.5 mm: The energy level structure and the Stokes shift

The energy level structure of a step-like GaInNAsSb/GaNAs/GaAs quantum well sQWd has been investigated by photoreflectance sPRd spectroscopy and was analyzed by theoretical calculations. In the active region of this structure, i.e., GaInNAsSb/GaNAs QW, we have observed PR resonances related higher order QW transitions in addition to the ground state transition. Based on calculations from experimental data, we have found that the electron effective mass in the active QW is 0.12m0 and the conduction band offset for GaInNAsSb/GaAs interface is about 0.85. The emission observed from this structure at 10 K has a small Stokes shift si.e., 6 meV and ,2 meV for as-grown and annealed structures, respectivelyd and is without the exponential-like tail at the low-energy side. Hence, we conclude that the incorporation of Sb atoms into GaInNAs alloy helps to achieve QW structures which emit light at longer wavelength and have quite narrow emission line and small Stokes shift. © 2005 American Institute of Physics. fDOI: 10.1063/1.1854729g