Deep electron and hole trap spectra and electroluminescence (EL) efficiency of green multi-quantum-well (MQW) GaN/InGaN light emitting diodes were measured before and after 6 MeV electron irradiation. Starting with a fluence of 5 × 1015 cm−2, electron irradiation increased the concentration of existing electron traps with levels at Ec−0.5 eV and introduced new electron traps with levels near Ec−1 eV. The latter are the well known radiation defects formed in the GaN barriers of the GaN/InGaN MQW region. The degradation of the EL efficiency after irradiation correlates with changes of the Ec−0.5 eV and Ec−1 eV electron trap density, suggesting these are effective non-radiative recombination centers. By sharp contrast, the concentration of the dominant hole traps with levels near Ev+0.45 eV decreased after, which eliminates these from the role of Shockley-Read-Hall defects actively participating in recombination.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials