Photoluminescence from exciton-exciton scattering in a GaAs1−xNx thin film

摘要

We have investigated photoluminescence u0001PLu0002 properties under high-density-excitation conditionsnat 10 K in a GaAs1−xNx thin film u0001x=0.008u0002 with a narrow band-gap energy of 1.34 eV. A PL bandnwas observed with a threshold-like nature, and its intensity was found to exhibit quadraticndependence on the excitation power. At the threshold excitation power, the PL-peak energy is lowernthan the energy of the fundamental exciton by the magnitude of the exciton binding energy that isnu00034 meV. The results described above indicate that the PL band originates from exciton-excitonnscattering, the so-called P emission, which is typically observed in wide-gap semiconductors withnlarge exciton binding energies. Furthermore, we have confirmed the existence of optical gain in thenenergy region of the P band using a variable-stripe-length method. © 2010 American Institute of