Determination of the optical band-gap energy of cubic and hexagonal boron nitride using luminescence excitation spectroscopy
Abstract
Using synchrotron-based luminescence excitation spectroscopy in the energy range 4-20 eV at 8 K, the indirect Γ-X optical band-gap transition in cubic boron nitride is determined as 6.36 ± 0.03 eV, and the quasi-direct band-gap energy of hexagonal boron nitride is determined as 5.96 ± 0.04 eV. The composition and structure of the materials are self-consistently established by optically detected x-ray absorption spectroscopy, and both x-ray diffraction and Raman measurements on the same samples give independent confirmation of their chemical and structural purity: together, the results are therefore considered as providing definitive measurements of the optical band-gap energies of the two materials.
- Publication:
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Journal of Physics Condensed Matter
- Pub Date:
- February 2008
- DOI:
- 10.1088/0953-8984/20/7/075233
- Bibcode:
- 2008JPCM...20g5233E