β-(AlxGa1-x)2O3因其优异的抗击穿及带隙可调节性在现代功率器件及深紫外光电探测等领域展现出巨大的应用前景，然而传统直接生长工艺的复杂性和难度限制了其进一步的发展。因此，本文采用较为简单的高温扩散工艺在c面蓝宝石衬底上成功制备了β-(AlxGa1-x)2O3纳米薄膜。利用X射线衍射、原子力显微镜、扫描电子显微镜和紫外-可见分光光度计对其进行了表征。由于高温下蓝宝石衬底中的Al原子向Ga2O3层扩散，β-Ga2O3薄膜将转变为Al、Ga原子比例不同的β-(AlxGa1-x)2O3薄膜。实验结果显示：当退火温度从1 010 ℃增加到1 250 ℃时，薄膜中Al的平均含量从0.033增加到0.371；当退火温度从950 ℃增加到1 250 ℃时，薄膜的厚度从186 nm增加到297 nm，粗糙度从2.31 nm增加到15.10 nm；当退火温度从950 ℃增加到1 190 ℃时，薄膜的带隙从4.79 eV增加至5.96 eV。结果表明高温扩散工艺能够有效调节β-(AlxGa1-x)2O3薄膜的光学带隙，为β-(AlxGa1-x)2O3基新型光电子器件提供了实验基础。

β-(AlxGa1-x)2O3 presents great applications in modern power devices and deep ultraviolet photoelectric detection for their excellent anti-breakdown and tunable band gap. However, the complexity and difficulty of the traditional fabrication processes limit their further development. In this work, a relatively simple high temperature diffusion process was used to successfully prepare β-(AlxGa1-x)2O3 nano films on c-sapphire substrates. The films were investigated by X-ray diffraction, atomic force microscope, scanning electron microscope, and ultraviolet visible spectrophotometer. Since Al atoms in sapphire substrates will diffuse into the Ga2O3 layer at high temperatures, β-Ga2O3 thin films will be converted into β-(AlxGa1-x)2O3 thin films with different ratios of Al to Ga atoms. It illustrates that with the increase of annealing temperature from 1 010 ℃ to 1 250 ℃, the average content of Al in the films increases from 0.033 to 0.371. Meanwhile, the thickness of films increase from 186 nm to 297 nm, accompanied by the roughness increase from 2.31 nm to 15.10 nm with the increase of the annealing temperature from 950 ℃ to 1 250 ℃. While increasing the annealing temperature from 950 ℃ to 1 190 ℃, the band gap of films increases from 4.79 eV to 5.96 eV. The results suggest that the high temperature diffusion process can effectively adjust the optical band gap of β-(AlxGa1-x)2O3 thin films, providing an experimental basis for novel β-(AlxGa1-x)2O3-based optoelectronic devices.