[21a-C101-1~10] 13.8 Optical properties and light-emitting devices

△ [21a-C101-4] 【Highlighted Presentation】Improved emission homogeneity of InGaN quantum wells on vicinal (0001) substrates by insertion of Eu-doped GaN as surface-smoothing layers

〇(M1)REO YAMATO¹, SHUHEI ICHIKAWA^1,2, ATSUSHI TAKEO¹, JUN TATEBAYASHI¹, YASUFUMI FUJIWARA¹ (1.Osaka Univ, 2.Research Center for UHVEM)

Keywords:GaN:Eu, macrostep, InGaN

III-nitride semiconductors are promising materials for optical devices. To achieve highly efficient optical devices, a reduction of lattice defects is required. Growth on vicinal (0001) substrates is one of the most effective techniques to reduce threading dislocations in GaN. However, GaN layers grown on vicinal (0001) substrates form macro-steps on the surfaces due to the step-bunching effect, and such surface structures cause compositional fluctuations in InGaN quantum wells (QWs). We have previously reported that the vicinal (0001) GaN surfaces with macro-steps are dramatically recovered by introducing a Eu-doped GaN (GaN:Eu) layer as an interlayer . In this contribution, we fabricate InGaN QWs on vicinal (0001) GaN surfaces after inserting GaN:Eu interlayers and investigate the indium incorporation behavior. From the optical properties of the InGaN QWs, we elucidate that the GaN:Eu interlayers strongly suppress wavelength fluctuations and enhance indium incorporation in the QWs, as a result of the improved surface morphology and appropriate strain-release.