IMPACT IONIZATION LUMINESCENCE OF INGAN ALGAN/GAN P-N-HETEROSTRUCTURES/

The luminescence spectra of InGaN/AlGaN/GaN p-n heterostructures with reverse bias sufficient for impact ionization are investigated. The in jection luminescence of light-emitting diodes with such structures was examined earlier. A strong electric field is present in the InGaN act ive layer of the heterostructures, and for small reverse bias the tunn eling component of the current predominates. Avalanche breakdown comme nces at voltages V-th>8-10 V, i.e., similar to 3E(g), (E-g is the widt h of the band gap) in the absence of lightly doped structures. The lum inescence spectra have a short-wavelength edge corresponding to the wi dth of the GaN band gap (3.40 eV) and maxima in the region 2.60-2.80 e V corresponding to the maxima of the injection luminescence spectra in the active layer. The long-wavelength edge of the spectra in the regi on 1.7-1.8 eV may be associated with deep recombination levels. Mechan isms of recombination of the hot electron-hole plasma in the strong el ectric fields of the p-n heterostructures are discussed. (C) 1998 Amer ican Institute of Physics.