InAlN薄膜的变温椭圆偏振光谱研究

Investigation of In AlN thin film by temperature-dependent spectroscopic ellipsometry

为了研究In Al N材料的光学参数随温度的变化特性,采用变温椭圆偏振光谱(25～600℃)测量技术对In Al N合金材料在193～1 650 nm宽光谱范围内进行了表征。利用Tauc-Lorentz振子模型描述和拟合变温椭偏光谱测量数据,得到了In Al N薄膜的光学常数(n、k和α)随温度的变化曲线。由变化曲线可见,在温度50～600℃,光学带隙从4. 56 e V减小到4. 35 e V,折射率峰值对应的能量则从4. 61 e V减小到4. 37 e V。两者都随温度升高而减小,其变化规律符合Varshni方程的预期。结果表明,在600℃以下测试温度条件下,In Al N合金材料的光谱和光学参数没有发生突变,说明In Al N合金材料具有高的热稳定性,并未发生影响材料光学性能的晶体结构变化。

In order to investigate the optical property variations of InAlN with temperature,InAlN alloy was characterized by temperature-dependent(25~600℃)spectroscopic ellipsometry in the spectral range of 193~1 650 nm.The optical constants(n,k andα)of InAlN thin film were fitted by temperature-dependent ellipsometry using the Tauc-Lorentz oscillator model.At the temperatures of 50~600℃,it was seen that the optical bandgap decreases from 4.56 eV to 4.35 eV,and the energy corresponding to the peak of refractive index decreases from 4.61 eV to 4.37 eV.Both of them decrease with the increase of temperature,which accords with the law of Varshni equation.The results show that no significant changes in spectra and optical parameters were observed under the test temperature conditions below 600℃,which indicates that the InAlN alloy has a higher thermal stability and has no effect of crystal structure changing on the material s optical properties.