Raman spectroscopy of BeO at low temperatures

Polarized first-order Raman spectra of BeO crystal were recorded at various temperatures to study the variations in frequencies and intensities associated with some of the phonons. At 35 K five modes were assigned to be fundamentals at 338.1 682.6, 726.7 and 1085.8 cm−1. The different scattering geometries were utilized to study the directional dependence of the dipolar phonons. Two peaks at 703.6 and 1093.7 cm−1. were the quasi-TO and LO modes, respectively. Both the frequency and the intensity of the phonons increase with decreasing temperature. The mode at 682.6 cm−1 was examined in more detail at several temperatures.