Raman analysis of aluminum nitride at high temperature

The Raman spectra of aluminum nitride were measured over the temperature range from room temperature to 1273 K. Frequencies of the E21, A1(TO), E22, E1(TO), A1(LO) and E1(LO) phonon modes are 252, 614, 658, 672, 894 and 912 cm− 1, respectively. The Raman peaks of A1(TO) and E22 modes are shifted toward lower frequency with temperature, which indicate that the compressive stress in the compact of aluminum nitride relax gradually when temperature is increased. The width of the Raman peaks of the A1(TO) and E22 modes are also broadened with increasing temperature. The powders of aluminum nitride readily react with water vapor in the air to product Al(OH)3 or AlOOH. These reaction products will decompose at elevated temperatures; this will affect the measurement of the Raman spectra.