Origins of efficient green light emission in phase-separated InGaN quantum wells

Yen Lin Lai, Chuan Pu Liu, Yung Hsiang Lin, Tao Hung Hsueh, Ray Ming Lin, Dong Yuan Lyu, Zhao Xiang Peng, Tai Yuan Lin

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52 Citations (Scopus)


Green-light-emitting InGaN/GaN multiple quantum wells (MQWs) with high luminescent efficiency were grown by metalorganic chemical vapour deposition (MOCVD). The microstructure of the sample was studied by high-resolution transmission electron microscopy (HRTEM) and high-resolution x-ray diffraction, while its optical behaviour was analysed in great detail by a variety of photoluminescence methods. Two InGaN-related peaks that were clearly found in the photoluminescence (PL) spectrum are assigned to quasi-quantum dots (516nm) and the InGaN matrix (450nm), respectively, due to a strong phase separation observed by HRTEM. Except for the strong indium aggregation regions (511meV of Stokes shift), slight composition fluctuations were also observed in the InGaN matrix, which were speculated from an 'S-shaped' transition and a Stokes shift of 341meV. Stronger carrier localization and an internal quantum efficiency of the dot-related emission (21.5%), higher than the InGaN-matrix related emission (7.5%), was demonstrated. Additionally, a shorter lifetime and 'two-component' PL decay were found for the low-indium-content regions (matrix). Thus, the carrier transport process within quantum wells is suggested to drift from the low-In-content matrix to the high-In-content dots, resulting in the enhanced luminescence efficiency of the green light emission.

Original languageEnglish
Article number020
Pages (from-to)3734-3739
Number of pages6
Issue number15
Publication statusPublished - 2006 Aug 14

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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