Comparative Study on the Luminescence Properties of Violet Light-Emitting InGaN/GaN Multiple Quantum Wells with Different Barrier Thickness

The photoluminescence (PL) characteristics of two violet light-emitting InGaN/GaN multiple quantum well structures with different GaN barrier thickness, grown by metalorganic chemical vapor deposition, are investigated. It is found that for the sample with thick GaN barrier layers, the polarization effect in InGaN quantum wells is promoted. According to the temperature-dependent PL measurements, it is considered that the localization effect in a thick-barrier sample is enhanced which may be attributed to the increased growth time of GaN barrier layers. It is surprising to observe that at low temperatures, the PL spectral widths of the thick-barrier sample are smaller than those of the thin-barrier sample, although the distribution of In content in InGaN well layers may be more inhomogeneous for the thick-barrier sample.