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Determination of the optical band-gap energy of cubic and hexagonal boron nitride using luminescence excitation spectroscopy

2008; IOP Publishing; Volume: 20; Issue: 7 Linguagem: Inglês

10.1088/0953-8984/20/7/075233

1361-648X

D. A. Evans, Andrew G. McGlynn, Brian Towlson, M. Gunn, Daniel C. Jones, Tim Jenkins, R. Winter, N.R.J. Poolton,

Graphene research and applications

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.