Photoluminescence of InGaN/GaN multiple quantum wells grown by mass transport

We report on studies of an In0.12Ga0.88N/GaN structure with three 35 Angstr om thick quantum wells (QWs) grown by metalorganic vapor phase epitaxy with employment of mass transport. The mass-transport regions demonstrate a thr eading dislocation density less than 10(7) cm(-2). The photoluminescence (P L) spectrum is dominated by a 40 meV-narrow line centered at 2.97 eV at 2K. This emission has a typical PL decay time of about 5 ns at 2 K within the PL contour. An additional line with longer decay time (about 200 ns) is obs erved at an energy about 2.85 eV. The position of this line shifts towards higher energies with increasing excitation power. The data are consistent w ith a model, where the PL originates from at least two nonequivalent QWs, w hich could be realized due to a potential gradient across the layers. (C) 2 001 Elsevier Science B.V. All rights reserved.