Electron irradiation effects in GaN/InGaN multiple quantum well structures

Capacitance-voltage profiles, admittance spectra, deep-level spectra, current-voltage characteristics, and microcathodoluminescence (MCL) spectra were measured before and after electron irradiation of n-GaN/InGaN multi-quantum-well (MQW) structures typical of the active region of GaN/InGaN blue light emitting diodes. Electron irradiation produces strong compensation of the conductivity in the MQW and introduces interface traps with ionization energies of 100 and 190 meV, in addition to a broad band of interface traps closer to the middle of the bandgap, acceptor traps near E-c - 1.1 eV and hole traps near E-v + 0.9 eV in the GaN barriers and at the GaN/InGaN interfaces in the QWs. The dose of electrons at which measurable changes occur in the MCL spectra is 10(15) cm(-2), while measurable changes in the electrical properties are observed after doses exceeding 10(16) cm(-2) electrons. (c) 2007 The Electrochemical Society.