The temperature dependence of the infrared absorption and Raman spectra due to boron in diamond

Raman scattering and infrared absorption characteristics of B-doped CVD diamond have been studied as a function of the temperature. First order Raman measurements show that the energy and the width of the Raman line depend on the acceptor concentration and, in particular for N > 10 cm, the peak becomes asymmetric. This is due to a Fano resonance interaction, already reported in literature for samples with similar boron concentrations. The dependence of the Raman energy on temperature is reported; it is shown that the shift to lower energy due to anharmonic processes can be described by the Klemens model. Raman data have been compared to infrared absorption results previously obtained. The Fano resonance is also observed in infrared spectra at 1332 cm for samples with lower boron concentrations. The comparison of these features shows that two different processes take place.