Spectroscopic Ellipsometer is employed to study the optical properties (including complex refractive index and bandgap) of pristine and doped AlN (Ti and Cr) films as a function of doping concentration and temperature (273 K–573 K). Pristine AlN, Al_1−xTi_xN (x = 1.5, 3 and 4 at%) and Al_1−xCr_xN (x = 2, 4 and 6 at%) films are grown on Si(100) substrates using magnetron sputtering technique. The crystal structure and chemical composition of the as grown films are analyzed using Grazing Incidence X-ray Diffraction (GIXRD) and X-ray Photoelectron Spectroscopy (XPS) techniques, respectively. The optical properties of Ti, Cr doped AlN films at a wider range of energies as well as different ambient temperatures are reported. To determine the complex refractive indices, the measured ellipsometric parameters I_s and I_c are fitted using a five layer model with Lorentz oscillator dispersion relation. As far as the bandgap region is concerned, both the real and imaginary parts of the refractive index show significant changes near the bandgap. It is observed that, the real part of refractive index of AlN increases monotonically with the increase in Ti doping and opposite in Cr doping. The extinction coefficient is relatively larger for Cr-doped AlN compared to Ti-doped AlN films. With the increase in doping concentration, the bandgap is found to decrease rapidly for Cr-doped AlN in comparison to Ti-doped AlN films. Additionally, a significant change in the complex refractive index of doped AlN films is observed with temperature.

光谱椭偏仪用于研究原始和掺杂的 AlN（Ti 和 Cr）薄膜的光学特性（包括复折射率和带隙）作为掺杂浓度和温度（273 K-573 K）的函数。原始 AlN、Al _{1− x} Ti _x N（x  = 1.5、3 和 4  at %）和 Al _{1− x} Cr _x N（x  = 2、4 和 6  at%) 薄膜使用磁控溅射技术在 Si(100) 衬底上生长。分别使用掠入射 X 射线衍射 (GIXRD) 和 X 射线光电子能谱 (XPS) 技术分析生长薄膜的晶体结构和化学成分。报道了 Ti、Cr 掺杂的 AlN 薄膜在更宽的能量范围和不同的环境温度下的光学特性。为了确定复折射率，测量的椭偏参数I _s和I _c使用具有洛伦兹振荡器色散关系的五层模型进行拟合。就带隙区域而言，折射率的实部和虚部均在带隙附近显示出显着变化。观察到，AlN 的折射率实部随着 Ti 掺杂的增加而单调增加，而在 Cr 掺杂的情况下则相反。与 Ti 掺杂的 AlN 薄膜相比，Cr 掺杂的 AlN 的消光系数相对较大。随着掺杂浓度的增加，发现与 Ti 掺杂的 AlN 薄膜相比，Cr 掺杂的 AlN 的带隙迅速减小。此外，观察到掺杂的 AlN 薄膜的复折射率随温度发生显着变化。