TEMPERATURE-DEPENDENCE OF THE CUBIC BORON-NITRIDE RAMAN LINES

The first-order Raman spectra of single-crystal cubic boron nitride for the range of 300 to 1830 K are presented. The Stokes and anti-Stokes components of both the TO (GAMMA) and the LO (GAMMA) modes are analyzed for their Raman shift and width variation with temperature. The cubic boron nitride converted to hexagonal form in vacuo at 1840 K. The first-order Raman shifts up to this temperature, in units of cm-1, can be written as nuBAR=a0+a1T+a2T2 with coefficients 1060.6 cm-1, -0.010 cm-1 K-1, and -1.42x10(-5) cm-1 K-2, respectively, for the TO (GAMMA) mode, and 1307.6 cm-1, -0.003 cm-1 K-1, and -1.46x10(-5) cm-1 K-2, respectively, for the LO (GAMMA) mode. It is shown that the Raman linewidth variations with temperature can be fit to the predictions of a three- and four-phonon-interaction model. Comparison with earlier results from natural diamond is made.