氮化铝结构的高温Raman光谱分析

本文测量了氮化铝在不同温度下的Raman光谱 ,并确定了氮化铝的光学声子模E2 1、A1(TO)、E2 2 、E1(TO)、A1(LO)和E1(LO)Raman散射峰的频率 ,它们分别为 2 5 2cm- 1、6 1 4cm- 1、6 5 8cm- 1、6 72cm- 1、894cm- 1和 91 2cm- 1,其中光学声子模A1(TO)、E2 2 的Raman散射峰比较明显。随着温度的升高 ,A1(TO)、E2 2 散射峰的频率向低波数方向变化 ,表明氮化铝粉末压制体中存在的压应力逐渐减小 ;这两个散射峰的半高宽逐渐增大 ,说明随着温度的升高 ,存在氮原子和铝原子的扩散使得氮化铝粉末压制体中晶体结构逐渐发生变化。由于氮化铝粉末本身在空气中易与水蒸气发生反应 ,生成的Al(OH) 3 或AlOOH在加热过程会发生分解 ,干扰样品高温Raman光谱测量。

Analysis of the Raman Spectra of Aluminum Nitride at High Temperature

The Raman spectra of aluminum nitride at different temperature have been measured The frequencies of E 21 ,A 1(TO),E 22 ,E 1(TO),A 1(LO) and E 1(LO) phonon are determined They respectively correspond to 252 cm -1 , 614 cm -1 , 658 cm -1 , 672 cm -1 , 894 cm -1 and 912 cm -1 The Raman peaks of A 1(TO) and E 22 mode are especially obvious and shift toward lower frequency with temperature increased,which indicate that the compressive stress in the compact of aluminum nitride relax gradually The width of the Raman peaks of A 1(TO) and E 22 mode broaden with the increasing temperature which show that the diffusion of nitrogen and aluminum atoms in the compact of AlN will result in the change of the crystal structure of AlN Because the powder of AlN will react with the vapour of H 2O in the air easily, Al(OH) 3 or AlOOH, the product of the reactivity, will decompose during the heat, which will disturb the measurement of the Raman spectra of AlN