Influence of small indium content in quantum barriers on the luminescence properties of InGaN/InGaN double-quantum wells

The optical emission of four InGaN/InGaN light-emitting diode samples with double-quantum wells (DQW) with varying indium content in quantum barrier (QB) layers are investigated by high resolution X-ray diffraction, temperature-dependent photoluminescence excited by a 325-nm He-Cd laser and a 405-nm semiconductor laser, photoluminescence microscopy, and by atomic force microscope. We demonstrate that the introduction of a small amount of indium in quantum barriers can improve the uniformity and change the luminescence properties of quantum wells. It is found that the InxGa1-xN DQW has the best uniformity when the indium content x in QB layers is 0.15%.