Comparison of optical properties in GaN and InGaN quantum well structures

Shigefusa F. Chichibu, Amane Shikanai, Takahiro Deguchi, Akiko Setoguchi, Rikuro Nakai, Kazumi Wada, Steven P. DenBaars, Takayuki Sota, Takashi Mukai, Shuji Nakamura

Research output: Contribution to journalConference article

Abstract

Static, field-modulated, and time-resolved spectroscopic measurements were carried out to compare the electronic structures between AlGaN/GaN binary and GaN/InGaN ternary single quantum wells (SQWs). The internal field exists across the quantum well (QW) naturally induces quantum-confined Stark effects, namely the redshift of the QW resonance energy and separation of electron-hole wavefunction overlap. Thus AlGaN/GaN SQWs exhibited a weak luminescence peak due to the presence of nonradiative channels. However, optical absorption and degenerate pump-probe measurements revealed that excitonic character still remains for the thin QWs having the well width nearly the same as the bulk free exciton Bohr radius even under high electric field as high as 0.73 MV/cm. A slightly In-alloyed InGaN SQW exhibited bright luminescence peak in spite of the pronounced effective bandgap inhomogeneity in the QW, which was confirmed by the point excitation and monochromatic cathodoluminescence mapping methods to have the lateral potential interval smaller than 40 nm. Therefore the light emitting area of the potential minima has the size defined as 'quantum-disk' [M. Sugawara, Phys. Rev. B, 51, 10743 (1995)]. Carriers generated in the InGaN QWs are effectively localized in these region to form localized QW excitrons exhibiting highly efficient spontaneous emissions.

Original languageEnglish
Pages (from-to)98-106
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3896
Publication statusPublished - 1999 Dec 1
EventProceedings of the 1999 Design, Fabrication, and Characterization of Photonic Devices - Singapore, Singapore
Duration: 1999 Nov 301999 Dec 3

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Chichibu, S. F., Shikanai, A., Deguchi, T., Setoguchi, A., Nakai, R., Wada, K., DenBaars, S. P., Sota, T., Mukai, T., & Nakamura, S. (1999). Comparison of optical properties in GaN and InGaN quantum well structures. Proceedings of SPIE - The International Society for Optical Engineering, 3896, 98-106.