Deep Electron and Hole Traps in Electron-Irradiated Green GaN/InGaN Light Emitting Diodes

Abstract

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 x 10(15) cm(-2), electron irradiation increased the concentration of existing electron traps with levels at E-c-0.5 eV and introduced new electron traps with levels near E-c-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 E-c-0.5 eV and E-c-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 E-v+0.45 eV decreased after, which eliminates these from the role of Shockley-Read-Hall defects actively participating in recombination. (c) 2017 The Electrochemical Society. All rights reserved.