高压下AlN纳米线的介电性质

利用高压X射线衍射和高压原位电化学阻抗谱法研究了AlN纳米线的高压结构和电学性质.研究结果表明:AlN纳米线的电学参数均在22.6 GPa发生了突变,该突变与样品发生了从纤锌矿到岩盐矿的结构相变相关.岩盐相中晶格对电子的散射在电传导中起主导作用;不同于纤锌相中的长程传导,岩盐相中存在短程传导,且其作用随压力增加而增大;纤锌相的介电损耗峰在1Hz且不受压力影响;岩盐相的介电损耗峰随压力减小且向低频方向移动.本研究将为AlN及其相关材料的进一步研究和应用提供实验依据.

The Dielectric Properties of AlN Nanowires under High-pressures

X-ray diffraction and in-situ alternate current impedance spectra of AlN nanowires have been measured under pressures up to 31.8 GPa by using a diamond anvil cell. The results show that the electrical parameters of AlN nanowires changed discontinuously at 22.6 GPa, which is related to the structural phase transition from wurtzite to rocksalt phase. The scattering of electrons by the crystal lattice in the rock salt phase plays a leading role in conduction process. The electron conduction in the wurtzite phase is mainly long-range conduction. Short-range conduction exists in the rocksalt phase, and the effect of short-range conduction is enhanced with increasing pressure; The dielectric loss peak of the wurtzite phase appears at 1 Hz and is not affected by pressure, while the dielectric loss peak of the rocksalt phase decreases with increasing pressure and shifts to the low frequency direction, indicating that pressure can effectively control the dielectric properties of the sample. This research will provide experimental basis for further research and application of AlN and related materials.