Lattice Infrared Spectra of Boron Nitride and Boron Monophosphide

P. J. Gielisse, S. S. Mitra, J. N. Plendl, R. D. Griffis, L. C. Mansur, R. Marshall, E. A. Pascoe

The fabrication of highly dense, highly polished compacts consolidated from monocrystalline cubic boron nitride at very high pressures and temperatures has enabled us to record the infrared reflection spectrum of cubic boron nitride from 80 to 550°K. For annealed compacts, the reststrahlen peak reflectivity of about 85% could be obtained. Analysis of data by a damped-oscillator model yields TO (k≃0):1065 cm-1, ε0=7.1, ε∞=4.5 and LO (k≃0):1340 cm-1. Infrared transmission measurements on small single crystals were obtained with a beam condenser. Eleven absorption peaks were observed between 600 and 3000 cm-1. These are assigned as combinations of four Brillouin-zone boundary modes: LO 1232 cm-1, TO 1000 cm-1, LA 685 cm-1, and TA 348 cm-1. The reflection spectrum of hot-pressed compacts of boron monophosphide single crystals measured between 600 and 1000 cm-1 showed a monotonic decrease of reflectivity from about 15 to 9% with an extremely weak reststrahlen band around 825 cm-1. The estimated values of long-wavelength optical modes are TO (k≃0):820 cm-1, and LO (k≃0):835 cm-1. The results thus suggest an extremely low effective ionic charge (∼0.25) for the crystal. Additional deduced physical properties of cubic boron nitride and boron phosphide are discussed. © 1967 The American Physical Society.

DOI badge Download BibTeX How to cite Download dataset

Materials
Curve 1
Temperature K: 298 Wavelength Range, µm: 5.56-24.8 Geometry θ θ': ~0° Composition (weight percent), Specifications, and Remarks: Powder of cubic BN subjected to high pressure and temperature for consolidation; ground and polished; specimen annealed in air at 623 K for 15 min; density approaches theoretical value of 3.50 gm cm⁻³.
Curve 2
Temperature K: 78 Wavelength Range, µm: 5.04-13.5 Geometry θ θ': ~0° Composition (weight percent), Specifications, and Remarks: Similar to the above specimen and conditions except specimen not annealed; data extracted from smooth curve.
Curve 3
Temperature K: 298 Wavelength Range, µm: 5.04-15.9 Geometry θ θ': ~0° Composition (weight percent), Specifications, and Remarks: Above specimen and conditions.
Curve 1
Temperature K: ~298 Wavelength Range, µm: 2.65-23.8 Geometry θ θ': ~0°~0° Composition (weight percent), Specifications, and Remarks: Single crystal platlets with cubic structure (30 µm thick); grown at very high pressure and temperature; 1010 ohm-cm electrical resistivity; data extracted from smooth curve.
Curve 2
Temperature K: ~298 Wavelength Range, µm: 2.62-24.3 Geometry θ θ': ~0°~0° Composition (weight percent), Specifications, and Remarks: Single crystal platlets with cubic structure (30 µm thick); beryllium-doped; grown at very high pressure and temperature; 10¹ ohm-cm electrical resistivity; data extracted from smooth curve.
Curve 1
Temperature K: 298 Wavelength Range, μm: 11.1-13.5 Geometry θ' θ'': ~0° -0° Composition (weight percent), Specifications, and Remarks: BORON PHOSPHIDE, BP; Very fine single-crystal particles hot-pressed; cubic structure; ground and polished; data extracted from smooth curve.