Photoluminescence, reflectance, magnetospectroscopy of shallow excitons in GaN

Brian Skromme, H. Zhao, B. Goldenberg, H. S. Kong, M. T. Leonard, G. E. Bulman, C. R. Abernathy, S. J. Pearton

Research output: Chapter in Book/Report/Conference proceedingConference contribution

35 Scopus citations


We report several new aspects of the excitonic properties of heteroepitaxial GaN grown on sapphire or 6H-SiC. In particular, we observed the n = 2 free exciton associated with both A and B excitons (which are distinct from the n = 1 C exciton) using reflectance and 1.7 K photoluminescence. We also studied the behavior of the n = 2 A-exciton using magnetoluminescence in fields up to 12 T. The large diamagnetic shift and splitting positively confirm the identification, yielding an exciton binding energy of about 26.4 meV. Several-previous identifications of the n = 2 free exciton yielding a smaller exciton binding energy are probably in error, based on our results. We have also detected the two-electron replica of the neutral donor-bound exciton for the first time in GaN and observed its splitting pattern in magnetic fields to 12 T. This feature is 22 meV below the principal neutral donor-bound exciton peak, independently of strain shifts in the overall spectrum. It yields a precise donor binding energy of 29 meV for the shallow residual donor in material grown by metallorganic chemical vapor deposition and gas-source molecular beam epitaxy, considerably smaller than that of the residual donor reported earlier in hydride vapor phase epitaxial material (about 35.5 meV).

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium - Proceedings
EditorsF.A. Ponce, T.D. Moustakas, I. Akasaki, B.A. Monemar
PublisherMaterials Research Society
Number of pages6
StatePublished - 1997
EventProceedings of the 1996 MRS Fall Symposium - Boston, MA, USA
Duration: Dec 2 1996Dec 6 1996


OtherProceedings of the 1996 MRS Fall Symposium
CityBoston, MA, USA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials


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