Anomalous composition dependence of optical energies of MBE-grown InGaN

I. Fernandez-Torrente, D. Amabile, R. W. Martin, K. P. O'Donnell, J. F.W. Mosselmans, E. Calleja, F. B. Naranjo

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)


A direct comparison of the optical energies of MBE- and MOVPE-grown In xGa1-xN epilayers of similar InN content is performed for the first time. The InN fraction in the 7 MBE samples examined ranged from x ∼ 0.11 to x ∼ 0.35 while the range in available MOVPE epilayers is [0, 0.4]. Wavelength Dispersive X-ray (WDX) and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopies were used to measure composition and local structure (alloy character) of the samples. Cathodoluminescence (CL) spectroscopy in situ, ex situ photoluminescence (PL) mapping and large-area optical absorption spectroscopy were used to measure various optical energies. The composition dependence of the optical energies is determined by the growth method. The absorption bandgap and luminescence peak energies vary linearly with x for both growth methods, suggesting a near-zero value of the bowing parameter. But the energy intercept at zero InN content in MOVPE samples is close to the wurtzite-GaN bandgap of 3.4 eV at room temperature, as expected, while the equivalent for MBE samples falls near 3.2 eV.

Original languageEnglish
Pages (from-to)673-676
Number of pages4
JournalMaterials Research Society Symposium - Proceedings
Publication statusPublished - 1 Dec 2003
EventGaN and Related Alloys - 2003 - Boston, MA, United States
Duration: 1 Dec 20035 Dec 2003


  • semiconducting indium compounds
  • absorption spectroscopy
  • cathodoluminescence
  • energy gap
  • light emitting diodes
  • metallorganic vapor phase epitaxy
  • molecular beam epitaxy
  • parameter estimation
  • photoluminescence


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