三氧化二镓的高压拉曼光谱研究

High-pressure Raman spectroscopy of Ga_(2)O_(3)

β-Ga_(2)O_(3)是一种宽禁带半导体材料(E_(g)=4.8 eV)。研究β-Ga_(2)O_(3)在高压(高应力)条件下的相稳定性和晶格动力学特性对其材料应用具有重要的参考价值。目前关于Ga_(2)O_(3)在高压下的晶格动力学特性研究较少,且Ga_(2)O_(3)的β→α的高压相变压力仍然具有争议。本工作采用基于金刚石压砧(DAC)的高压拉曼光谱技术研究了Ga_(2)O_(3)的高压拉曼光谱特性与相变行为。研究发现β→α高压不可逆相变发生在22 GPa。本工作给出了α-Ga_(2)O_(3)和β-Ga_(2)O_(3)各拉曼振动模的压力系数与格林艾森参数,并发现β-Ga_(2)O_(3)的高频和低频拉曼模在压力系数方面存在着较大的非谐特性。

As a wide-band gap(E_(g)=4.8 eV)semiconductor,the phase stability and lattice dynamics about the Ga_(2)O_(3) under high pressure provide us the valuable information for its applications.However,the lack of the study on the phase stability and the lattice dynamics of Ga_(2)O_(3) under high pressure makes the phase transition point remains controversial.In this work,we find that the irreversible β→αphase transition occurs at 20.1-22.7 GPa by using the high-pressure Raman scattering based on diamond anvil cell(DAC).We also provide the Grüneisen parameter and pressure coefficient of α-Ga_(2)O_(3) and β-Ga_(2)O_(3).Our results also suggest that the pressure coefficient of β-Ga_(2)O_(3) exhibits anharmonic properties.